I like the Modes idea, however it should be an optional rule for games that are psionics-heavy/centric. It doesn't make a lot of sense to use them in a game where a single PC is the only psychic thing around, around the different modes were just as effective against nonpsionic enemies.
As for the at-will selection idea, they could be chosen in Discipline suites, or per power, depending on how a player or GM would see it handled in that world. I am also up for Disciplines being optional alongside Attack/Defense modes, as they aren't necessary unless the campaign world has a lot of psionic depth, or the DM just really wants that depth in the PC. I do want to see each of those represented in some way though, as they are good ideas and allow things to not be so basic and static.
Now we just need to get the good word out to Mr. Mearls on this at-will-into-Augments psionics, so it can be properly hammered out with R&D, playtesting and polls for the community.
If done right, you could use this class to create a suitable Psion, Psychic Warrior or even a Soulknife, depending on the powers you pick and the Augment paths you choose. A Psi-Weapon path could allow you to make mindblades with various abilities and types at higher levels, but if you were tapped for PP you would always have that fallback basic mindblade at-will power. Physical powers that allow your character to alter their shape, size, or speed could be Augmented into making a psychic-shifting warrior, while doing the same with telekinetic/telepathic/metacreative paths to create a dominant psychic caster.