Well, arenas are necessary if after you kick them, TCA comes and arrests you for good. While in arenas you can let your anger flow without thinking about any consequences to your opponent or yourself. That is, if Respawners work good.
They should have followed UC2 style I think. SP and ladder separated, good for both, plus everything's nicely explained and with humour.
Actually respawners dont always work good, some matches the last kill is a real one a true deathmatch. Theres a moment in UC2 thats rather entertaining when sobek shoots anubis in the arena, there is actually parts where you can die though outside of the arena and you start from the last checkpoint. Tribes V did something similar as well with integrating arena matches into the storyline.
Brock got killed by Gorge for example, Xan got pretty stuffed up by Malcolm and so on so people do die or get really badly wounded in UC/UT.
I pictured more an assault type thing, perhaps like TF2 with the TC maps I think it is where you can push through different ways maybe even a turn based map like RTS games have for conquest type.
Theres nothing wrong with being out numbered though, it woulda been kewl to get swarmed by a krall ambush having a 3:1 ratio and more of an invasion feel to it.
Theres so much Epic coulda done but I really think a war-tourney was a bad move! Onslaught never really fit in with the rest of the tourney anyways, neither did invasion so it makes sense to build up something around that more akin to Unreal but on the battlefront, as you mention XMP which takes Unreal 2 and makes it a warlike MP mode.
Its obvious Epic got DM, CTF down pretty well but for me warfare could have been more or even there could have been modes which play on warfare but arnt exactly the same. We see alittle asymmetry come through already but some of that wont always play well in a PvP scenario, maps like this could be flagged as SP/Coop only and you can only play those during the campaign or when you select invasion/assault type modes.
Something like that anyways I could dribble on about it but I wont