Why is proximity detonation always put on the healing staff bar? I thought that skill was a key feature of the build and you'd want it on the DW bar for more damage, but all the builds I see put it on resto staff bar. Is it actually not a very important skill for the build?
I don't play one, but odds are it's placed on that bar because it's their buff/healing/defensive bar. Most if not all damage in the game updates based on the stats of the character upon actually doing damage. So by the time you bar swap, the detonation will get front bar stats.
Proxy det is an instant cast with delayed damage, so most people will be on front bar when it goes off at least if things go to plan
It's the same reason sorcs will run curse on their back bar. The damage calculation is based on what your stats are at the time the damage is done, not at the time of cast. So back barring it allows you to load skills on your front bar that aid in burst and damage or are required to use during the bomb and not as a load up for the bomb.