I don't even enjoy sky arena anymore....it's a tough balance (I know), but I want a challenge, not to just be frustrated. Can we ease up on the difficulty?
when setting up your defense in the arena, it would be fun to be able to choose the map you're on. Maybe select from a few different options. Would give a little more flare to arena.
Healing is not needed at all...Exploration quests are waay too long at 12! When you upgrade them, the time should go down, not up. I see no recognizable difference between a boss fight and a normal one. I'd suggest much tougher fight quests, different paths to take, damage types (physical/magic), more character types (spearmen/swordsmen/archers/fire mage/ice mage, etc), and pretty much anything to give the game more depth and content :) Sorry - that's a lot to 'suggest' :).