It's a pretty much unnecesary hack, and I still remember the days when Acmlm hacked the living excrement out of the board until Sean wiped everything clean and installed a no-hack vBulletin. Speed increased 100% overnight.
EoFF is fast enough for me, 'cause I'm on cable--but we also have to look out for the 56kers out there, and for that reason, I'm reluctant to hack the board without a significant gain from it.
As for promoting spam, I don't think it really would. Without the quick reply box, a reply is still only one more mouse-click away. If people are determined to spam, they'll take that click.
