You're not supposed to be able to use any skills while transformed, this seems intended.
The "trigger when transformed" modifier seems to be specifically for this, so it makes sense that it can still trigger skills.

In the demo, before the game came out, there was simply no option for using other skills, because there was no grid or modifiers. You spent points learning and getting modifiers for specific skills.

The transformation thing is meant to be a "basic attack" build.
I don't have the feral class on my character, but maybe you'd be able to use sentinel's minion triggers? I'm not sure if those triggers are from you or from the minions themselves. They also get a fusion transformation with weretiger that summons minions when you transform.