Putting my thoughts in a new post so I can edit the first one for ease, also because winning on message count in #conc-general has taught me to keep things separate to move up the leaderboards.
Regarding AA: I think it's fine with current preset values. It's clearly faster than TFC in some aspects and slower in others - regular air-strafing vs things like the 'spin fast to get out of a tube and build horizontal speed' respectively - but I think that's fine.
Due to the code shenanigans in TFC/FF for AA being unhelpfully mysterious, copying FF did not properly replicate all behaviours as desired. I'm not sure this will be attainable unless someone (I'm squarely looking at hlstriker for this one) can figure out a loophole that would allow closer behaviour. At the end of the day, I'm fine with strafing being a little easier (harder maps) and losing tube strafes (less motion sickness) if this is where we're at.
Lumia's adaptation for slowing down with S feels great to me, and I think the balance between the two is in a solid place.
Regarding timers: I can't disagree strongly enough with the new 'separate timers' for HH/thrown concs. I believe it fundamentally breaks the game, as you will effectively need two distinct pitch values for the timer sound to account for both timers. This can be seen on any map if you try to HH (pitch lines up fine with the current preset) vs trying to juggle around.
I don't know how you could ever match this up - the game won't know what you're intending to do with a conc until the end of the timer, as if you're juggling up, you're holding - like you would an HH, so shorter timer - a conc until it's released when you start to fall, very shortly before the detonation. How would pitch ever work/line up in this situation?
If ending up with using one fixed timer makes the game "easier" simply because it has removed some degree of randomness or variance from TFC, is this not ultimately better for a game dedicated to speedrunning in the first place? Maybe having a fixed timer this whole time (with the new zippy AA) is why things felt so much easier for the older players, and how Zike has ended up becoming precbot2000 in such a (relatively) short amount of time.
Of all the "it doesn't have to be 1:1 TFC" things on the table, fixed timers for consistency and reliability would certainly be the major change I'd support.