James McMurray said:
The 10 minutes of meditation is most definitely a drawback. Unless your DM is not up to snuff, there will be times when you don't have the luxury of ten minutes of meditation.
Not up to snuff?
So, if this is a drawback for psionic characters, how much of a drawback of studying or praying for spells for an hour is it for normal spell casters? In the case of gaining extra PP, especially for long duration powers, it seems that it would be a lot less of an issue for psychic characters than for normal spellcasters.
With regard to normal encounters, you're right. They do not always announce themselves 10 minutes ahead of time. However, there are still a lot of situations where they do. For example, you can prepare ahead of time in a lot of city encounters where you are going to a set location. Ditto for dungeon encounters. For both of these, it's a toss up. Sometimes you'll have time to perpare. Sometimes not. Mostly, it is wilderness encounters where 10 minutes preparation time is rare since you tend to not encounter creatures from a mile or more away and have them close.
The real issue here, though, is that they tried to balance fairly potent abilities against a 10 minute preparation time and an hour duration. The question is whether that is balanced.
The +2 Str, +2 Dex, +2 Con one, for example, gives +1 to hit with all attacks, +1 damage to most attacks (mighty longbow anyone?), +1 AC, +1 Reflex saves, +1 Fort saves, +1 hit point per level. For all intents and purposes, that's fairly close to raising a combat level for that hour for a combative character.
Is this balanced?
Well, compare it to Cleave. A single attack, but only when you have multiple opponents and only when one of your opponents drops. So, at equal levels of ability (the status quo of combat), that might occur one round in five out of one combat in two (half of the combats, you are probably fighting one on one to some extent). So, you might get a chance to cleave three or four times a day max (on average), depending on the types of combat you are getting into.
Compare it to Dodge. +1 AC versus one opponent every round of combat where you are probably only in combat for 10 to 30 rounds a day on average.
So, if you know you are going to be in combat, the feat is very powerful. If you do not know, it may or may not be.
The question is whether that is balanced.
I'm not sure of that, but I do not think the Third Eye power is balanced at all. It's just a boatload extra PP, most or all of which will be used up first thing in the morning.