Just an FYI, the Psionic feat you're thinking of is Wild Talent, though it doesn't grant psionic powers, it only allows you to count as psionic (meaning you can take psionic feats). While it does provide alot of interesting options, it doesn't grant actual powers.

Martial Study lets you learn a single manouver, however it has a built-in limit that it can only be taken three times.

If you're eager to have such class features, I might go as far as to expand the options (for instance, add in a psionic feat that does grant a power, or feats to gain shadowcaster mysteries and auras etc).

Another option, as someone pointed above, is to maybe provide such options a different way. Maybe grant an additional feat every X level, but it must be one of these newer feats - though check with your players first, having such additional powers might just seem like extra and unneeded book-work for them.