You just need to enter this command in Terminal:
defaults write com.apple.dock show-expose-menus -bool no
After restarting the Dock (with killall Dock or with another utility), you will now have a Dock where clicking and holding on an application icon gives you the same menu as the one you get with control-clicking. And it’s instantaneous. Yey!
And just so you know, changing this setting does not disable the other feature, i.e. the “Minimize windows into application icon” feature. It still works. You just don’t have to deal with slow Exposé crap anymore.
Great tip aimed to those who can’t stand the new Exposè menu feature.