I'm not altogether bothered by lack of PVP in D3, but am annoyed that there is this Nek the Brawler fellow moping around in the game but is totally ignored cos what he is offering ain't what we want. Time, effort and resources were spent on creating him but he's pretty much irrelevant at this point.
a) it is higly unlikely a whole new PVP module will ever be worked on (due to lack of financial incentives for Blizzard, balancing issues for dev team, etc)
b) Nek the Brawler training ground already exists
Why not add a "kill count" to Nek?
So when you run around in Nek's traing ground and knock off a couple of other players, these "kills" gets tallied and added to a cumulative total against your profile.
No new battle maps, no re-balancing, just add a counter to something that is already there but right now is about as useful as bewbs on a bull.
To keep the development effort to an absolute low budget minimum, don't even record how many times you get wasted (cos no-one needs to be reminded about how often they got owned), just show how many times you've nailed someone else.
No, this isn't a proper PVP solution, but hey Nek's just hanging around looking like he's willing to offer free bj's just to get some love and attention, so why not put him to work.
A slightly more adventurous idea might be to add an option to set an "entry fee" to go into one of these duelling sessions. Kind of a wager using in game gold or materials, goes to a pool collectible upon first to 5 kills or somesuch. Though don't want to over reach here...