Powers in Mass Effect Andromeda are covered on this page.
There are no Character Classes and you'll be able to pick and choose what powers you want to use. Specialization results in play style bonuses, giving titles similar to old classes like Adept and Vanguard. There will be benefits for specific specializations. What we don't know if these are synergies or base stat bonuses. We do know however that there are 7 of them. It is possible that they fit the mold of the original classes plus a generalist. As the game progresses, a narrative reason will allow you to respec.
Powers themselves will now have individual cooldown timers rather than a global cooldown for all powers. This is to allow players more freedom in how they operate, and gives them the flexibility to expend them all or use them in combinations. This is true across single and Multiplayer.