Well I hear that the 620 has improved the AF speed considerably and I thought had a way to reduce the mirror movement again, although it doesn't have the 2nd sensor like the still-unique E-330 (to Olympus' line).
But don't forget that Sony came out with their own "LVA" equivalent - instead of the half-silvered mirror to the 2nd sensor, they slightly adjust the main mirror angle to hit a 2nd sensor vs. the OVF. So I imagine it's as fast as the E330. And for 'macro' liveview, I'd assume other implementations may be acceptable (nearly static, up-close subjects).
I have noticed, the more I've been shooting in general, that we are suffering a bit of 'digital lag' in our LV monitor, which may cause us some delay beyond just the LVA not having the extra mirror movement. Then again, using the 'main' sensor for live view will have that as well as potential heat issues on the main sensor.
Very curious to see how "micro 4/3rds" pans out for digital viewfinder enhancements. But I'm with you overall jlyle - haven't been tempted to upgrade from the E330 yet. I have however begun to notice a bit of age-related farsightedness, which means I might need to change my current mask choice (Hydro-optix) to be able to focus close on guages and my camera LCD screen. (sigh) It'll be hard to give up the field of view it offers though....
Battery life really isn't an issue. The camera battery in full LV all the time still lasts longer than my strobe batteries, so I swap them all out at the same interval.