:lol Boring? If you find the Joker challenges boring then I've got bad news for you, buddy! You won't be getting a good portion of the achievements you want (the Batman challenges).
They're far from boring. I've taken a real liking to the combat system and am always looking for ways to top myself, now (41x is my max, as the Joker). Then there's the Predator challenges which are ENTIRELY different when you play as the Joker (Gargoyles aren't available, L2 doesn't activate x-ray vision, 1 bullet and 1 pair of Chattering Teeth). It's quite awesome, to say the least.
I'm guessing you aren't playing on Hard since you haven't found the need to upgrade your armor. :lol
Therefore, I suggest you go for all the unlockables to the left (combo ones). You'll be glad you have all those combat options when you get into the big brawls.