The only problem with the arena is it becomes really pricey really quickly (As I think you've seen by now. Stupid ninjas stabbing me while I'm studying. -_-) Which also makes the trophies pricey as well. Maybe I just haven't gotten to the monster level where my mullets scale to be worth as much as gold in DII.
Doing the math on the clicks
5 to find monster. (~6 sec per click to scan page)
1 to click on monster (~2 sec)
1 to fight or run (~3 sec) (+1 click & 5sec for failed run)
1 for Vs. screen (~2sec)
8 clicks pre fight (~37 sec pre fight)
1-2 clicks to loose impossible fight (~1s)
2-5 clicks to win easy fight (~2s)
10+ clicks on even fight(~2s)
~3-4 clicks for the average fight (~7 sec)
At least, that's pretty close to what it feels like. That's not counting missed monsters cause I zoned into page refreshing. Sometimes I it comes more quickly cause I get lucky, but I stand by that 5:1 is a bad ratio.
Another thing that might work better is after winning a fight you have the option of "tracking" the monster or "looking for trouble". Basically it's a guaranteed fight after winning a fight. I'd suggest having the fights gradually scale (10-25% more difficult each time) and maybe a better chance at treasure for each fight (5% per fight perhaps).
Another thing I've noticed is I always seem to get caught running away from super powerful monsters. If the the group can one shot me, they should send their minions (1/2 the power) to chase me down instead of wasting their time. Maybe bump the success chance of running to 90% and if you successfully flee 3 times you elude all combat. You could increase the death penalty to even the score.