As per psionics I have never been a fan of them. Not in 1E, not ever. They just seem pointless. They come off like a lame magic system with a monk twist. "It's the internal power of the mind causing this effect" You mean the spell-like effect that seems to have the same source as all the various Ki powers of the Monk/Ninja etc? Wow. Awesome. Not a fan.
As for PrCs they have been overdone and I wouldn't weep at all if they were left by the wayside. Same for new core classes for the most part. Some are nice (Knight, Beguiler, Archivist and Swashbuckler spring to mind) but with 3.X we got waaaaayyyy too many. The concept of class variants with Feats etc is pretty neat. Like making the Assassin a class variant of the Rogue or the Beguiler as a variant Sorcerer or the Archivist as a variant Bard. Kind of like how they did the variants in the 3E Unearthed Arcana which was IMO an outstanding product. Speaking of which using the Weapon Group Proficiencies that book had would be acceptable to me.
Monster books get a huge thumbs up from me though. Not like the last couple of MMs from WotC were like though. Focus on diversity and quality rather than "look at this awesome collection of sick undead".