REO is great, I think he's probably the best NRS games player there is. His legacy in MK9 is the greatest, etc. (Yes I think he was and is better than PL). That said I have to disagree, I think the street fighter series is much more technical and difficult to master than NRS games. I'll concede that I think capcom players are mistaken with how easily they think they can pick up Injustice because as has been stated by others there are a ton of match ups and variables that need to be learned and memorized. But at the end of the day that's all you need to do, from an execution and mastery stand point I think NRS games pale in comparison to capcom games in terms of difficulty. PL has been delving into Capcom games, and gets bodied most of the time by mid tier players. As opposed to Chris G who has historically come into NRS games and placed top 8 (With lower tier characters like Green Arrow and Reptile).
All of that said having a low execution barrier and skill cap is not a bad thing. NRS games are more approachable to new players which is great as it just serves to feed a stronger population (Now if NRS could just release a title with decent netcode).