I wouldn't straight up ask them to swap for th Bionic. They would probably think you are only trying to get the newest phone out there.
How many replacements on your current phone have you received?
And, you better get back to stock or they will likely claim you voided the warranty and blame it on you for rooting.
Agree on both accounts. Go to stock Android.
And when you complain don't bring up any phones. Do it in a polite way and mention that you've had multiple problems with the TB and that you're wondering if it's problems that other phones experience too. I'd wait until tomorrow or Friday (probably Friday since it doesn't look as bad). Key thing is to not ask for it but explain all the difficulties that have been unique to this specific handset, at least, IMO this is what works.
I've never done it at Verizon but have done it (once) with another device I was having serious issues with (and it was a known manufacturing problem). Not one to abuse the system, but in that case they were willing to swap it out for a like-device without any additional charge.
Be polite and don't get upset, IMO it works out best that way in most cases. It's not the employee's fault your handset sucks.