For 3 stars:
Nope.
In the last 6 months these are the 3 stars that have been released. Let me know if I’ve forgotten any:
Squirrel Girl 21/01/2015
Luke Cage 07/01/2015
Gamora 04/12/2014
Rocket & Groot 25/11/2014
Mystique 09/11/2014
Blade 28/10/2014
Dr Octopus 31/09/2014
Colossus 15/09/2014
Beast 01/09/2014
Luke Cage is a defensive stud, yes.
Blade is a serviceable support if you don’t have Daken.
Mystique has a tiny tiny niche as part of the “winfinite” combo with Marvel Now Magneto.
And Rocket and Groot is generally considered “good enough to level.”
I would only really define Luke Cage as an “elite” or “powerful” character among those 4.
But outside of those four, there isn’t a single character on that list that is worth leveling.
Most of the powerhouses in the 3 star range, such as Thor, Hood, Patch, Daken, Captain America, Black Panther and Magneto have been around forever.
There is one exception; Loki’s remake has made him elite. But that was a revamp of a long time unusable character. Dr Doom’s remake made him playable in certain niches and Daredevil’s remake made him not a joke…but still kinda sucky.
Even in the 4 star range, there isn’t ALL that much power creep.
Yes, Xforce’s buff was insanely strong and 4hor was not properly tuned prior to release.
But the last 2 4 star releases indicate that power creep has not taken effect yet.
Elektra: Garbage of all garbage.
Starlord: Conceptually okay, but countdown tiles makes him useless in a practical sense.
D3 has done well to prevent power creep in the past. Instead of releasing more powerful characters, they are instead eliminating the outliers; Ragnarok, 2 star Thor, 2 star Wolverine, Spider Man, Magneto, Sentry. All nerfed to prevent the requirement of power creep.
However, unless Thor and possibly Xforce follow suit, power creep may be required if D3 wants to continue its cash flow.
But the bets are on the top 2 being nerfed, rather than stronger characters being released. It has been D3’s pattern and I don’t expect them to rethink that strategy any time soon.