These sites aren't particularly snappy on my dual-processor G5, so I'm not sure why you expect them to run like silk on your handheld. ITT is a bit of a special case, as the latest theme seems to be designed with zero efficiency in mind. Hopefully we'll see some improvements with further revisions from Reggie.

Zoom tends to do weird stuff with a lot of the AJAX-y multi-line text-entry areas. This feature will probably improve a lot over the next couple of MicroB releases.

I'd hardly call fullscreen browsing "mandatory", I spend a lot of my time browsing in windowed mode. Hiding the toolbar isn't particularly necessary, either, as the horizontal dimension (the most important dimension) isn't affected by it. Though, perhaps a show/hide hot-corner/button sort of deal wouldn't be entirely unwelcome.

Both MicroB and Opera have easy workarounds for getting the d-pad set up for page-up/down. If you're so lazy as to not want to do that, holding the d-pad will get you line-by-line scrolling.

Just focus on the whitespace. There's a lot of it these days, and it's not that hard to hit.

This has a lot to do with the fact that Apple doesn't have to worry about two types of touchscreen input (thumb and stylus), they have no contextual menu tap'n'hold to worry about, and that there's no text-selection process to worry about (that, and they don't have to deal with the N800's noisy touchscreen and its weird input drivers). The issue is more complicated than you think, and has its roots in system-level stuff that MicroB (well, the browser UI) really doesn't have much control over.

Yes, it's not perfect, but it's not an entirely clear-cut issue either.