you can solo molten core, most of ZG, onyxia, aq20. BWL is quite a bit harder even with 5-boxing, its a lot easier when you have multiple people esp for first boss, but it is 5 mannable (i cleared the whole instance once 5 man and don't ever want to go back). AQ40 is kind of 5-boxxable, its a bit rough and you will die a lot, i don't think you will get stuck at Twin Emps though. ZA is 5 mannable easy.