I'm with OP in this, it just makes better design sense to have enemies be a similar level in the same zone. This way you don't have to paradoxically be a high rank to get to a low rank area, and it keeps the high rank people in the high rank areas where they belong.

On another note, because of the way the engine loads enemies, sometimes higher level aggroing mobs will pop in right next to you if you're on a lower spec computer. It happens to me sometimes (before you ask, my computer exceeds the minimum requirements that SE posted, if it's inadequate SE should post higher ones) with that Peiste mentioned before as well as the ants that are inexplicably guarding the path from Black Brush to Drybone. I can kind of guess where they are now, but all it takes is that processing delay or a little server/comcast lag and bam! Oneshotted.

This isn't a problem if you're dealing with mobs around your level since you have time to respond when you're getting hit, but when you have mobs 20 levels above you roaming around the starting zones for no discernible reason, there's no chance. It's not "exciting", it's just annoying.