I saw a thread related to this on the official forums, but I can't post there and wanted to see what you guys thought. I personally don't mind if PvP becomes a big part of the game, but I have a few concerns.
1) I don't want to see the PvE content take a back seat to PvP... EVER. I played DC Universe for a while and got my fill of PvP there. I don't want to have to do PvP simply because there is more of it to do than PvE.
2) I really hope that they don't make PvP and PvE gear and content mixed. What I mean is, I don't want PvP gear to be among the loot drops of a PvE event, or the other way around. Maybe make PvP gear solely craftable / bought, not quested.
I guess my big fear is that PvP will at some point become required to succeed in PvE content. I wouldn't want to see people discouraged because they absolutely despise PvP and can't do certain things because of it.