Exactly Lax and what I had envisioned, but communicated poorly.

I really don't know how folks don't use a system that functions like mine. Trying to get aggro on an add or targeting the next mob in a sequence seems severly ganked if everytime you swich your main's target, your DPS follows. Like I said, the only thing I haven't yet optimized is an easier way to switch my DPS target when the current target is still alive. What I do now is simply hit F1 (which passes to all windows and, as you'd expect, "targets self") and resume smashing my DPS button. (Voila, new target acquired and DPS starts burning it down.)

EDIT: I'm purely a PVE guy so far thus my needs to switch mains has been few and far between. However, I'd gladly switch to a FTL system for the inevitable PVP itch and for those rare occassions (will be less rare as I venture into Heroic dungeons) where my main goes down.