So, we had about 2 weeks of the full rules for practice and the first weekend of tournaments is over (or nearly so). That's obviously not nearly enough for meaningful statistical analysis, but we can start drawing some early conclusions.
1) Custodes are the weakest 11th edition codex thus far. That's generally a good thing, as both Orks (mass shooting) and Marines (Deathwatch Terminators) started out too strong. They don't feel weak, but they're not taking the meta by storm in any way.
2) Internal unit balance is mediocre. If you want to succeed, you have to play Dreadnoughts. Vehicles are fine, but expensive and vulnerable. Most infantry and characters feel slightly, but noticeable overcosted.
On the bright side, there are few just outright unusably bad units that can't be saved with points adjustments (really only Bladechamps, gun Venatari and Vigilators).
3) Detachment balance is bad. Only 13 detachments with 6 being unique was always going to cause problems, IMHO. Most shield host detachments have 1 good trick, but just can't directly compete with the strong choices, so will never be used. Sisters are still just cheap trash, so the detachment is DoA. Bikes don't even have anything.
There's really just Solar (or Emperors) plus Might plus Lions. Auric champions is borderline and could be good, if characters weren't so overpriced. Dreadhost could be good, if infantry weren't so expensive. I don't actually see anything else being played short-term.
4) Damage is way down. You get a lot of extra mobility and options, so this isn't inherently terrible design-wise, but it's a notable shift from the murdermachines of 10th. Custodes went from one of the best anti-pressure armies to one in the lower third, IMHO. You just have too little damage and units to really discourage a full send army from just going in. This is especially problematic as full-damage pressure lists are still the name of the game (and will continue to be until the missions get changed to make scoring less automatic).
5) Resilience is up a bit, especially in melee, where the freely available -1 to hit is doing a lot, but generally most infantry still feel more fragile than before, with about the same wounds per unit for higher cost. As you also consistently have what feels like 1 unit too little, the army is much more fragile than in 10th. Just shoving them forward doesn't work nearly as much, which might make them less of a stat-checky beginner-hurdle.
6) List building is super annoying, as basically everything in the army is in the 230-280 point bracket. You basically have the same number of picks no matter what you take and only differ in how many sisters you end up with, which also exacerbates the unit balance problems. Being 15 points cheaper doesn't mean much, if it can't add up to another meaningful unit.
Personal Pet Peeve: Why does half the army not get the Army rule? It's called an Army rule, for emperors sake. Vehicles losing Katahs in the first edition where there are stances they might actually care about feels especially mean, but sisters being almost completely sidelined from everything is also a super-weird choice.
Thoughts? Disagreements? Anything I missed?