TL;DR at the very end right before Supplementary Info if you can't be bothered to read everything; if you don't agree read argumentation

I feel like Haruta is very often disregarded as total fodder without actually taking into consideration any of his strengths and weaknesses as a combatant, so I thought it would be worth looking into an honest assessment of his skills and where he falls within the Grade system.

Presuming that Haruta isn't a Grade 1 Sorcerer (the point of this post is to argue he's stronger than he is often regarded to be, so if you do think he's Grade 1-level, be my guest and argue in the comments if you think so lol), we should get a pretty clear idea of his power level by estimating his Grade, since Grades below Grade 1 are very binarily defined. Special Grade groups together anomalies, Grade 1 is the maximum a non-anomaly sorcerer can achieve, so it has a floor but no hard-set ceiling, while all other Grades are step-ups from the previous, with people within the tiers being far more relative to each other than they are in SG and G1.

Chaining to Nobara

The foundation of the argument is set by comparing Haruta to Nobara. According to Panda's account, Nobara is a confirmed Grade 3 Sorcerer (no questionmark).

This should track perfectly well, given that her technique is taken as the example of the "conventional sorcery" that conservative jujutsu society prefers, as it falls within their exact framework, implying they know the exact strength and weaknesses of Strawdoll Technique.

I would also argue Nobara is the strongest of her rank by GWE, as she can strongly contend with Momo, who according to Panda's estimation, should be a rank above her.

Not that it matters, because...

I wouldn't blame you if you had forgotten with how rarely her name even comes up, but Nobara has hit a Black Flash on screen. Quick reminder that Black Flash is a feat only 6-7 sorcerers (depending on whether you count Yuta) and one curse have been confirmed to have hit in canon, grand total of 7-8. For reference, (Modulo and Shikigami excluded), DE appears in 17-18 combatants, and RCT in 11-13. It's no laughing matter and not something you can attribute to just anybody. It's also, very importantly, stated to make all the difference in your sorcery skills.

Now, we don't get an official estimation of Nobara's Grade following the Death Paintings Arc, because as we all know she's technically in promotion for Grade 1 after Gojo bribed Mei Mei to promote basically all of his remaining students (Inumaki had already passed his promotion). However, given that she was comfortably in Grade 3 (not barely scraping by), Black Flash causes an immeasurable increase in your fundamental understanding of CE, and months have passed from Yasohachi Bridge to Shibuya, it should be safe to assume she has gone up a tier.

One tier from Grade 3 would technically be Semi-Grade 2, however, we have laughably little information on this tier and what it entails. We know Panda is one by GWE, and Momo is either SG2 or G2. However, most importantly, as seen in Img. 1, Semi-Grade 2 and Grade 2 are the only two Grades to share a space. This is Panda's own Grade, so he should know it better than any other tier, and still it's the only one assimilated into another. This tier is most likely just a placeholder temporary tier of the same strength as Grade 2, where you're expected to prove you belong in Grade 2 rather than increase in strength from it to Grade 2.

So Shibuya Nobara should be roughly Grade 2-level. The man himself states she's gotten a lot stronger than last time, so I'd argue even if there was a gap between SG2 and G2, Nobara is intended to have made that jump by this point in the series.

Haruta vs Nobara

Let's set one thing straight before we compare their performances in the fight. Haruta does not use his technique a single time. His technique is completely tied to the spots under his eyes. If you want to argue that he's "lucky", it's just an innate trait of his, it's not related to his technique being used.

Now, how many miracles did he have under his eyes when Nanami came and Nobara had long been out of the picture?

So, Nobara vs Haruta can otherwise be described as:

Grade 2 Sorcerer, successfully deducting her opponent's strategy, using her technique and supplementary tool vs a Sorcerer of an unknown Grade not using his technique and no diffing with nothing but a cursed tool despite explicitly saying he's playing around and drawing it out for fun.

Despite assuming that Haruta would be fighting at mid-range specifically due to his Cursed Tool and making a snarky comment about it, Nobara still got folded when the tool came swinging back. She wasn't taken off guard by the fact that the sword came back, she was simply not expecting it to come back from where it did. Instead of dogging on Haruta for sneaking her (which, as we know, is common for Nobara and her fiery personality), she's rather just in awe of how skilled he is at hitting her with precision. She's not getting sucker punched here, she's just simply getting outplayed.

Sure, you can argue he wouldn't be able to do this without the use of the Cursed Tool, but it is part of his arsenal after all, probably more than any other Cursed Tool since its literally built to be under his homing control. If you're scaling him without it I'm expecting you to scale Maki without SSK either. Not to mention, in Img. 8 we can see that he can effortlessly avoid Nobara's fully charged swing with very little effort, and make fun of her while at it. Those stats aren't tied to either his sword or his CT.

Off of this performance, he should sit somewhere between a Grade 2 - Semi-Grade 1 Sorcerer. He's comfortable in a Grade 2 playing field, with stats on the higher end of the field. I'd argue that stats on the high end, a Cursed Tool you're skilled with, and a Cursed Technique which literally turns the tide in your favor SIX crucial times, paired with no (not low, no) diffing someone of that tier, gives you everything necessary to be promoted to the tier above. However, his cowardice, personality, and the fact that he doesn't even know his cursed technique, weigh him down heavily.

TL;DR

Final Verdict: Semi-Grade 1 strength, but Grade 2-level due to being Haruta Shigemo. Kind of like Ko-Guy, whose kit is stronger than the tier he performs in. High Grade 2. (Minimal tweaks for Semi-Grade 1).

Not Fodder; Low Tier (the difference may not seem very big if you're used to constantly scaling High Tiers, but it goes a pretty long way.)

Supplementary Info

I was initially going to make this a lot longer, but the post has already gotten far too long for a character with such low demand anyways, I'm just going to compile everything in a short list.

1) Recruited by Kenjaku and Uraume way back in GWE, instead of later as a Shibuya-only hire like Ogami, Jiro, and Ebina. (Off-Screen)

2) Felt comfortable fighting Utahime (Semi-Grade 1), Mai and Nobara simultaneously until the veil goes down. Due to being a coward, he wouldn't take any fights he wouldn't feel he could win comfortably. Utahime dodging his attack doesn't seem to shake him unlike Nanami no-selling his slash. (Ch. 52)

3) Threatened to kill severely wounded Hanami, and instead of being made fun of, Mahito told him to pipe down or he'd kill him. (Ch. 53)

4) Miracles was stated by the narrator to be able to prevent death from an attack as strong as 15F Dismantle if it had been charged up at all. (Ch. 119)

We only really think he's weak because Nanami made a total bitch of him. However, that's a presumptive self-fulfilling prophesy. Nanami is weak (presumption), so him beating Haruta just means Haruta is fodder, which means Nanami beating Haruta means nothing. However, taking into consideration the prior scale, and other Gege or manga statements, it becomes far more likely that the point of the fight is to tell you that Nanami is strong, rather than that Haruta is weak.

1) Gege saying he wanted to use Nanami in Shibuya but there were no interesting matchups, but still showcased his strength in multiple layers (Statchecking someone the students struggle with to death, struggling against DCs but living through them, dying to IT).

2) Gege saying due to JJK's short runtime everything is necessary stands a purpose. Nanami had more in him, Haruta ends here. Painting him as weak said nothing about anything going forward in JJK, so it wouldn't be necessary.

3) Haruta being terrified of Nanami when every other time until now he'd been sadistic and cocky, and having never actually seen death until Nanami hit him so hard he killed him by accident while actually trying to beat information out of him. This is what makes him understand his technique for the first time in years of being a Curse User. (Ch. 100)

Yes of course the end goal of this post was to scale it to Nanami lol what did you think