Swiny,
I've been away from Wow focusing on other things for a bit, but a plugin that allowed a player to target the closest healer would be great! (even better if there was a hotkey that we could map to change target to the closest healer).
As I've said before, I've been using CCs like EzRet in Combat bot mode and fighting in a crowd and then I spot a healer (I do have HHTD plugin so they're easy to spot), would be great to hit my hotkey and have my Pally switch targets to the closest healer (or a close one that was already damaged... either one works)
As I said, I use EzRet but if you created the plugin, then if we needed to, we could modify the CC that we are using NOT to override the selection. (within a short time, supported CCs would check to see if your plugin was enabled, or would give the user a checkbox to tell the CC not to override your plugin's targeting (like many CCs have LazyRaider options now)
In the beginning, we'd have to 'hack the CCs' to keep them from fighting a targeting plugin, but if it became popular (and this would be HUGELY popular with everyone who PvPs other than healers).
Once you had this completed to target healers, there is a second step that would make it 100% essential to everyone that PvPs. Give it priority options:
ie. My priorities would be:
1) Target flag carrier that is < 20% health
2) Target Healer within 15 yards that is <20% health
3) Target closest healer within range
4) Target flag carrier >20% health
5) Target any player <20% health within 15 yards
6) Target closest player within range
Then the plugin would go through my priorities top to bottom looking for a player that meets the criteria (the last one would have to be a final default). It should run the priority either after their current target died or is no longer in range, OR if I mash the hotkey to retarget.
That's what I would love to see... and yea, I know... it wouldn't be simple but it would change the game for PvP. Your toon would now really be looking to help a team win (and get more kills in the process - as we know, once the healer(s) go down, the rest follow).