All game companies force you to play their game their way. Very few change game mechanics or entire software design because people complain about it. Separate stats for PvE and PvP isn't just a math problem, it's a database problem. It's a data model problem. It's an Inventory display problem. It changes much of the game which was built around reading 1 collection of stats and using them. Easier to normalize damage and just adjust impact. That's a big change right there, quite a massive one. I'm not saying impossible, but large aspects that touch a lot of modules. All of which would need full re-testing from scratch. Not to mention double the testing needed for all balance testing. As a software developer I love (read: hate) it when someone says "Oh this is no big deal" when in fact they're asking for a complete foundation change.