Nail said:Part of the reason this power/feat combo is broken is because the Psion can make the sphere any size he likes.
So you can make 1' diameter fireballs at will? How about different shapes at will? After all, if you can change the size from what it says why not make it bend a little?
I think that since the spells say one thing it would be the players responsibility to find a rule that says they can make the size whatever they want.
Sure, they could manifest it at a lower level (down to the minimum) but that would still be pretty large plus make it much easier to dispel or the like. Note that you can do this with any spell or power. If you want to cast a fireball that does 5d6 and you are 20th level you just have to say that you are casting it at 5th caster level, but you cant go below that because it requires at least that much to cast it (there are exceptions, but this is just the general rule).