Elder-Basilisk said:
It's more like 3-4 feats, two of which are unnecessary at high levels, and two of which severely impede casting if used regularly. (Apply both to all your spells and it's like losing four levels). The advantage of the psion in this case is not just that he has options that take a sorcerer or wizard a feat, but that he has those options without the increased cost that sorcerers and wizards must pay to use them.
At higher levels, Combat Casting and Skill Focus allow you to shift your skill rank priorities to other skills. This is not a big deal for a wizard, obviously, who gets mondo skill ranks from his Int score, but it is arguably more useful for a cleric or sorc, whose skill points tend to lag. It's not a big thing, to be sure, and at high levels, exchanging feats for skill points seems to be a losing proposition, but arguably half of the problem is
getting the character to survive up to those high levels in the first place!
The key to using Still Spell, I would think, is to use it with low-level spells that are just handy in a tight pinch (or grope), like grease, ray of enfeeblement, enlarge person, and the poor wizard's lighting bolt (aka shocking grasp). That way you can save your higher level slots for the good stuff. That, and both Still and Silent only boost the slot up by one each. Keeping a
lesser metamagic rod of silent spell handy for the pins, though, can save you a feat.
And while yes, the psion can do this without any feat investment, Combat Casting, Skill Focus, Still Spell and Eschew Materials are useful outside of grappling as well. That said, grappling the spellcaster is a tactic that is great if used sparingly and it works, but isn't guaranteed to do so. (The easiest way to defeat an unwelcome grappler is to have a friendly rogue nearby just itching for something to be denied its Dex bonus. Sure, your caster may be frustrated for a round or two, but in my experience, allowing the rogue to shine by saving the wizard's bacon can make for some truly memorable moments. And if nobody wants to play a rogue, maybe see if you can pick one up via the Leadership feat if you can.)
As for Expanded Knowledge, well if it's a problem in your game, the easiest solution is to remove the feat or allow it to be taken only once. In my games I've seen it come up exactly one time, with the party Telepath (detective type power and feat selection) picking up sensitivity to psychic impressions at 5th level instead of the ubiquitous energy missile. So really, YMMV. You're the one in the best position to know what your campaign is like and what is appropriate to it. By all means, if something is upsetting the delicate balance of your game, put a stop to it.
Cheers,
Vurt