In general Arena KQ is a nightmare all around and in no way "fun" to do. I really only have 2 major complaints, and a couple suggestions on how they can be addressed.
1. AFK "players"
Annoying aspect, fairly easily solved. I'm aware that the game has a "jail" system that essentially locks players in a small area. Using that to jail afk players wouldn't solve anything immediately, but increasing the punishment exponentially would deter it even a little. 1 hour, 3 hours, 12 hours, 1 day etc.
Another potential idea would be denying KQ entry altogether, with similar time restrictions. Toggle the register button off.
2. SC Buffs
What's more fun than getting spawn camped by a lvl 70 mage with 12k hp doing 5k damage? Sitting in the jail map probably. Disabling SC buffs for arena would drastically change how people approach and actually play it. Where's the challenge when one team is charmed so hard that any one of them can solo the other team? Using +'d gear, scrolls, and HK buffs can change things, but at least both teams can reasonably have that or at least that player can be beaten.