That would work, Strangemonkey. You'd still have access to the two lynchpin 2nd-level seer powers if you were a 3rd level psion. I forgot about the kalashtar social bonuses, which would be a big help for this character.
If I were choosing two psychic warrior powers and was thinking about combat ability, I would give strong consideration to claws of the beast. It's the standard attack of the psychic warrior, with the following features:
- Manifest as a swift action, which is pretty close to a free action for our purposes
- Duration is 1 hour/level
- You can use your hands normally while claws are manifested.
- Damage scales as you pour more power points into it. It will "grow" with your character
-
It gives you two natural claw attacks at no penalty. If your regular class attack routine eventually improves past two attacks a round, this power does limit you to two attacks (at your highest bonus), but that shouldn't be a concern if you spend the rest of your career as a psion.
Don't forget that inertial armor also scales as you grow, adding +1 armor per 2 PP spent. So, at fifth manifesterlevel, you'd have a +6 armor bonus that sticks around for five hours. I can appreciate the idea of choosing compression/expansion for general utility, but it's hard to beat claws of the beast/inertial armor as foundational combat powers. You'll have so many power choices as you progress as a psion that you should be able to pick up compression or expansion a bit later if you choose. You could buy some dorjes with the powers in them to test their utility out before committing a power to them as well.