Agree with the sentiments about thieves, in my experience.

With regards to Paladins, can I ask why specifically they are favorable explorers? I think I am following, but I just want to be sure. They have good defenses/damage redux, self heals as well as good offensive output. Built in detect invis, though that isn't a huge draw, given the availability of detect invis. Turn undead seems decent for some areas. So, to my perception it seems that pally is good because they are really survivable and able to solo lots of things because of that, is that close to correct?