There isn't power creep. FFG gives the new ships roles by making them different, not more powerful.
The only OT ship that's weak is the X-wing and that's because it's a Wave I ship and the design priorities were different then.
When a new product wholly supplants an older one that fulfills the exact same function, you have power creep. I would say the B-Wing almost universally replacing the X-Wing is a fair example of power creep, but that's limited to generics, and luckily one of the few instances I can cite.
