Those people want best-first ordering and most sub threads are short and/or linear
that's a good point, even if it can be inconvenient for regular readers. As a regular reader, i don't mind at all though.
On the other hand, best-first or whatever is the ordering, tabbing can be made narrower so that deep threads do not show weirdly slim (maybe use different colors too). And also, for anon-users it is inconvenient to stop showing threads at a certain depth unless it is a performance problem/database access (in which case nothing beats that argument), i would suggest less left-tab and show threads all the way down. Keep the order as it is now. my 2 cents if anybody asked for them.