Yeah, but Tekken is explicitly a "martial arts fighting game," if that makes any sense. It's not as dull/realistic as Virtua Fighter, but it's still hand-to-hand combat. The Tekken team doesn't mind including clone characters, but NetherRealm is seemingly avoiding that with Injustice.Tekken is full of like 50 characters who all do various forms of martial arts, if they really wanted too, they could easily make a unique moveset for Powergirl, I could probably make one in like 10 minutes.
Power Girl's special moves would have to include the vortex breath, freeze breath, and heat vision, which Superman already uses, and then there's whatever Zod will have. A potential Martian Manhunter would have all of that, too. A fourth "Kryptonian power set" character doesn't seem worth the effort to me.
Batgirl's really only similar to Batman in name only -- there are a bunch of gadgets that Batman doesn't have in Injustice that could easily go to Batgirl. Power Girl is sort of tied down to the powers that Superman already utilizes.No. She has all the powers that Superman has. I suppose they could have her use them in a different manner, though. As batgirl would to batman.