The cw target audience are people who watch One Tree Hill, gossip girl, etc. so a teen Diana Prince show will have similarities to those other cw teen shows also which will obviously make many comics customers very angry.
Superman seems to be as powerful as the gods and this is true of all kryptonians and maybe also daxamites. One possible limit is the sun of our solar system which seems to be where kryptonians get their powers and not from all the stars in the universes.
Liefeld has already gone back to his own properties at extreme studios at Image. Most of the Hawkman stuff is probably from the editors or the dc architects. In the New 52, writers don't seem to have much freedom and just follow the dictation from the editors or dc architects. The rebooted Shayera Thal looks ok to me except for the bikini costume and the New 52 Hawkman is more powerful merged with nth metal.
Superman often has to battle other kryptonians like the phantom zone villains, evil gods from apokolips, martians, etc. so it is useful for Superman to know some kung fu. Maybe Clark is unemployed and can't afford kung fu lessons.
If the earth 2 title is cancelled, this might pave the way to reboot Jay Garrick, Alan Scott, Kendra Munoz Saunders, Al Pratt, Terry Sloane, Dr Fate, Solomon Grundy, Wotan, etc. back into the main earth where they can be more useful. For example, if Justice League needs more females, can try Kendra Munoz Saunders or other old characters like Helena Kosmatos, Yolanda Montez, Beth Chapel. Rebecca Tyler.
In the bronze age, both Superman and Lois Lane knew kryptonian kung fu altho Superman still got beaten up by Faora. In the Smallville tv show last few seasons, Clark did do some kung fu and maybe he learned it from the computer at the Fortress.