So not sure what you mean by impulse triggers?
For me, RT and LT work for accelerate and brake respectively, but it's never had any ffb on them like, say Forza 7.
I get ffb from the main controller when going over rumble strips, bumping other cars (or good old fashioned crashing haha) etc, but it seems softer than before.
Ignore all above if impulse triggers is a different thing hahaha!
The sound of the cars also seems.... less impressive. Still destroys Forza, and easy better imo than PC2, but some of the oomph seems gone.
Need to play more to make sure and settle in, haven't played for a couple months and stupidly not just before the update to remind myself, so I could genuinely compare.