I'm also attempting to minimize, but not totally eliminate html tables in favor of divs and spans, but only where it makes sense (making sense = less work + more value). Rendering overhead can escalate quickly for tons of html table tags which is especially true if you are viewing a page at IMX with many comments. One example is this post I made about my car, that now sees over a 100 visits a day and at least a few new comments per day.
Also, I'm using HTML 4.01 Transitional as my DTD and will NOT be fixing a div alignment bug related to that DTD in Internet Explorer 5 for Mac. That browser is dead to me (and based on my server logs, dead to everyone else too). Using that doctype affords me greater control over a few visual elements, and is a good place to be in terms of wide spread browser support. I won't achieve 100% compliance though, and I'm not concerned about that at all.
Comment posting will take on an added dimension of the user being able to choose an icon to go next to their comment. I have about 6 or 7 done so far, and have the tech worked out using a couple of Brad Choate's MovableType plugins (this one and that one). It all works in theory right now, but we'll see what happens in real practice. User data will also be saveable via cookies (finally).
Now, be warned that I'll be doing the implementation on the live site. I'm too busy and lazy to create a dev site, replicate my production environment, implement and then push the new templates. This is a small personal site and no one is going to lose money or hours of productivity if the site is down or weird for a few hours (and maybe days). I'm hoping to get this redesign implemented within the next two weeks, but real life is getting crazy right now. In the meantime, please have a look at the redesign preview and post your comments below. Thanks.