I am often (too often) in the situation of having to merge more than one user’s consecutive replies and I often find myself responding “this is a forum, not a chat , don’t hit the reply button each row you write”.
This is a bad behavior in a forum and I would personally prefer if users were allowed a number of consecutive replies limited by site settings or category settings (at least up to TL 3).
In this way users are forced to learn how to use forum tools properly, leaving the moderators free to do much more useful work.
A user trying to respond consecutively the second, third or fourth time will see a pop up that say
“No more than x consecutive replies are allowed. Edit your previous reply instead or wait for someone to answer you”.
newuser max replies per topic and
sequential replies threshold are different site settings from what I have proposed.
The first is specific only to new users (and not for consecutive replies), the second shows only a warning but does not prevent the publication of consecutive replies.
EDIT: maybe a setting by category rather than a global site setting could be much more useful.