This whole post just blew my mind! I'm going to have to read this over and over until I've figured it out. I'm new to MMOs and multi boxing. Just got my 4 knights to 11 and have gone sentinel with all of them. I think I'm going to stick to a group of only one class until I can get a handle on all of the abilities and stats.
Edit: just finished hammer station with my 4 sentinels at level 18. I'm pretty impressed by them.