I always have Gambit room for Self MP <20% - Charge and Self - Libra on all characters, and Enemy HP >70% - Steal on Vaan. Then there's other useful Technicks like 1000 Needles, which I use Gambit Foe: flying - 1,000 Needles on any melee characters. I will change it to Telekinesis when I can.

So yes, when you successfully utilise both Gambits and Technicks, the game is better. It's more fun, easier (in a sense), and can make your team pretty kickass.