You answered it! Playing for PvP. That's all I care about. In my opinion the act of "catching" Pokémon is simply mind-numbing (got a plus for that) and all I care about is racking in stardust.
I think the current battle system is also dull: opponents are static (can't switch in and out, or dodge) and I think having the ability to switch Pokémon in and out will make a huge difference
Edit: just got the psychedelic reference ::))