[quote=@Ghosthands]
A quick question about powers: how much specialisation can we have in our powers at this point? Can Jek's sentry turret, for example, have a rocket launcher attachment (as seen in the power's Rank 6 in ME3)? If not, will our powers improve as we progress through the story?
[/quote]

I'll let you decide what power rank you want with the powers, all the characters are supposed to be top of the line at what they do so it stands to reason that they are very capable with their own powers.