What MMO you from?
Healing is pretty defunct on MxO in terms of single target since merely being interlocked will negate your ability to heal anything but AoE. This lacks the joy and/or finesse that I enjoyed about PvP healing in WoW for example.
Upgrade master WILL help your team win, but you pretty much make yourslef as hated as it gets. You can occassionally kill things like that but against good players you will end up having to roll a LOT. This is not the old days when a UGM could sit and hold against 4-6 players until some bright spark loaded delete upgrade 
Because PvP in MxO is so goddam pointless heals don't really add a lot most the time. You have no objectives most of the time, no real downside to dying, no upside to winning. You don't do it for better gear, or even limited items. You do it for the joy of killing (which may or may not be related to an *I better than choo* mindset) or perhaps of testing the limits of ability. Can I kill 1 get out? Can I get 1 solo and kill before reinforcements? Can I outwit.outskill.outplay them. Neither Healing (which is so related in my mind to forcing through and making an objective) nor UGM provide those very well. Not for me anyhow.
Since you can switch trees at anypoint I would suggest grinding levels as MA/Guns (piece of pie, but by Gods it will take a long, dull time anyway. Hint to devs - decrease xp per level or increase rewards to make players less suicidal around 36-49). You can then easily switch to Hax/patcher for the last few assuming you'll grind PB3 missions as I did for absurd cash rewards.
Good luck and enjoy your time here. And /t madbent for powerlevelling - he loves that ****