One thing you should do is look at games that are nothing but PvP. Call of Duty online comes to mind. All the diffrent PVP modes, capture the flag, headquarters, death match team death match, etc. Thats what this game needs. Also the pace of those games is fast, so fast it gets you adrenaline pumping, which helps to increase the excitement.
Thats just my 2 cents, I have tried PvP serval times, but could never get into it.
I wonder how space Deathmatch (i.e., free-for-all) would work. Would tanks be thoroughly tested? Would Battle-cloaking BoPs be ideal, or instant targets?