Well I'm level 22 now as a pure DPS Squire, I still place some bouncer barricades down to keep enemies back, and usually upgrade them to level 2, then I just go bat shit insane with my sword, lol, and sometimes I'll place the slice n' dice barricade in a busy area since that can rack up some amazing DPS on a group of enemies, and I use my harpoons to take down flying enemies (And use it in narrow corridors behind a bouncer), I've been MVP quite a few times actually, lol. My brother is a pure Tower Apprentice, and seems to be enjoying it, but feels useless once he has no mana left, lol, I usually end up giving him the leftovers of mine, since I get so much from the kills I get anyway...
I've got to say, since I've got a build to follow and been learning the maps, it's become really fun, although I still can't beat some levels on hard, heck, I have trouble on medium on most levels, it's still really fun, I just need to level up a few more times so I can have my Heavy pet, lol.