I need a bit more
Druid, Lv 113
5/5 self destruct
etc... List all your hero
Werewolf would be a good choice to replace marauder
what happen to your executioner? everyone gets one at the start. He is good as well
Assassin is great for arena, but not so much for raids
The engineer is fun at low might, but you should replace him
I think that placement along your starting circle can really make a big difference in some battles (potentially more at lower lvls - you'd have to tell me!)
Sometimes it helps if I am attacking someone that sends out an assassin/ninja to put my assassin at the back of the circle with the rest of my force at the front. That way their hero meets mine closer to my crystal with the reinforcements closer - letting them get in hits before my assassin takes too much damage. This helps me get into 4 on 5 situations.
Also, if they sent their whole army down the same path, usually my assassin will sort of "fall" back - because they are getting in the last hit or something, so that another of my heroes steps up and starts taking the full brunt of the remaining attack.
Lastly, I think that it is important to remember that you get HB based on your ranking when your timer (as I think that it is different for everyone) hits zero. So, if you can, time up your battles so that you have as high a rank as you can when your timer gets down to nothing.