I don't know if a Final Fantasy game could work, especially since a lot of people want to actually USE the alt mode. Turn-based play would make that difficult.

 

I COULD, however, see a game where you gained levels as you progressed, unlocking special abilities. Let's say Trailbreaker unlocks a basic forcefield function at level 5, which he can then use in combat, or Hound unlocks an advanced holographic ability, allowing him to scan enemies and create holographic warriors to fight for him.

 

It would have to be real-time, so that as you defeated enemies, you gained levels. This would allow you to transform into a semi truck as Optimus, crush a few enemies, gain a level, transform again and blast a few stragglers, all without ever having to stop and select a skill or power.

 

DAMNIT! I made myself want my own idea again!

Well, I guess I was thinking more like the gameplay in Kingdom Hearts where you and your cohorts play more realtime. Or in Knights of the Old Republic.

 

Turn based would work, and TFing would be a turn. One move in alt mode would be Ram or Run-Down. Fairly ineffective for Bumblebee but for Prime....

 

Plus think about gestaults. Bring all 5 parts of a team together and form your own freaking Stage Boss to beat crap out of whatever you're facing. Great animation sequences, lots of 'boom' and it's a hit.

 

One super-move might be 'Summon Metroplex' with an upgrade later to Summon Fortress Maximus wherein they'd stride into the battlefields and unleash a terrible assault on the enemy.