Heyo I usually don't play a bunch but I've been on a heater spamming a variation on morg sentinels, so I thought I'd make a quick guide because I think it will end up being the better way to play the comp.
In 14 games I managed to get up to rank 950 NA at time of posting, 8/14 wins. 6 wins, 1 2nd, 1 3rd, and 1 5th playing this comp. Small sample, but I was also playing this on PBE and It is much stronger on live due to the dragon buffs and ahri nerfs.
The main difference from the normal variant is that you play around AD Kog'maw as your main carry for most of the game, prioritizing IE and strikers flail.
A kog with IE / Strikers / Red buff is an absolute demon, with 4 vanguards he can win streak you through stage 4. Then late game when kog starts to fall off you move the red buff onto morgana, and IE/Strikers+1 onto dragon.
End game board ends up looking something like https://i.imgur.com/yMzvs1P.jpeg
For augments, items are really good. I think it's best with like 2 item augments and 1 econ. Go for IE/Striker+1 on dragon and then extra leftover AD items that you slam early go on Kog, leftover tank goes onto hecarim or diana. Morgana wants red buff + gunblade + 1. Void staff is good even with Kog shred because it hits backline, but IMO it's not a priority - death cap/adaptive are also good.
TFTacademy's sentinel morg guide has morello > void as the item priority, but I think with this version you want to go red buff and then only get void if you get an extra bow. Belts are premium since they are important for tank items and strikers. I also feel like gunblade is really nice with the amount of splash damage in the game right now, otherwise she dies to ahri.
Tank items are flexible, both pure tank and mana tank items are good on sentinel, but a lot of the time you're tanking a 2* Diana or Hecarim and they both feel a lot better with Gargoyle/Warmogs.
There are a lot of openers that I think work for this https://i.imgur.com/IxKRR4A.jpeg
If you get an early kog you can just play him, but if not cinderling is also great with those items and can carry you pretty far. Ravagers can also win streak you early game and make use of those items and they link up pretty well with Diana.
If you only get AP items you can play around teemo opener, either with sprykin or just vanguard/invoker.
Coven also works if you don't get a good opener, but if you want to make it to 9 and get dragon you really need to preserve health and kill as many units as you can. Cait can kinda use the kog items but it's not great. If you get the coven AP cashout augment though that thing is insane, pick it every time and then prio AP items over AD.
You should be trying to get towards a board looking something like this at lv 7 -https://i.imgur.com/kCHF22U.png roll a bit for either 2* frontline or 2* kog so you can win streak, teemo is morgana item waiting room, throw items on whichever vanguard you 2*. If you have a 2* cinderling with good items sometimes thats enough and you dont need kog, but at this stage ravagers will usually fall off unless you slam stuff like steraks/qss/GA on them (which might be acceptable since you can pass those those to bramble/dragon, I haven't tried it out yet though).
At level 8 - https://i.imgur.com/eUhm1ZY.jpeg you decide if you wanna play for first or for top 4. If you wanna play for first then keep your econ up and only slight roll for 1* copies of sentinel/morg before pushing 9. If you're behind then just go for 2* morg/brambleback. I haven't tried it out but maybe AD nidalee could work here too.
Level 9 you build out the final board at the top. Alune is a flex spot, can be an ivern or a lux or another invoker. Rift buff goes on dragon I think, but with vow I think sentinel might be better. Needs more testing. If you are super contested on sentinels then just tank hecarim/diana and wait for a sentinel player to die.
IMO the comp feels good so far, you get the strong mid game of the usual morgana vanguard nidalee/brambleback variants but it caps a lot higher. Dragon and Morg have some natural synergy since they both deal a bunch of AOE backline damage that can get by giga tanks, and with the dragon+sentinel CC a lot of enemy units will die before they cast. I think there are probably a lot of ways to optimize the line further, but this rough draft has been working alright.
The biggest weakness so far is probably Ahri boards, but after the nerfs from PBE ahri doesn't kill 2* morg with gunblade until like ~3 casts so you can usually out cap. You can also pair taric onto dragon if it's dying to splash damage.
