Scott... I understand your frustration as it is not consistent across ALL of the Hero's. but I would want to suggest trying again.
Have you performed a MASTER RESET of the Hero?
If everything has failed have you asked for a 1.5 Hero back to enjoy your previous happiness?
Biggest problem I agree with the Hero is BT problems... unusual that ANY connectivity would digress...
Truly though, it is NOT the Hero, as I hate to say it because I know it's not helpful, the Hero I have in my possession works great, fluidly and without any major issues. Have you ROOTED? I know you SHOULDN'T have too, but it might provide the experience you are hoping for and will certainly gain you more support than you might expect from HTC or Sprint as the Dev's are on the job over at XDA.
I was reluctant to ROOT, but did so once I knew I could, if needed go back to 1.5, but once having the 2.1 on my phone, that was not longer necessary as the 2.1 DOES work better on quite a few fronts. I would strongly suggest that you consider rooting your phone... why? Well, I have and only loaded the plain 2.1 with ROOT and Recovery function, no crazy ROM's or anything... Once I did that, I removed some of the Sprint Bloatware and HTC stuff I didn't need.
I can tell you, subsequently to doing this, the HERO flies!!! No lag, no hesitation. Although I know you've had issues with the landscape keyboard, with ROOT there are fixes for that too... you could load different keyboards to the phone. With that, there is NO LAG I have experienced otherwise, calls, texts, etc.
I'm not posting to counter your argument as to the Hero being substandard, as I have experienced otherwise and only make suggestions so that you might experience the Hero as I have. I feel if you were to give it a whirl, you would be happier and get the life out of the handset you expect and not feel the need to move on.
Anyway,
Happy Trails!