This was discussed by the admins/mods (in brief) before the full removal, so I'll post some quotes from that thread so you can get some more insight on the decision:
DoubleThink said:
TBH I've never been a fan of the auto-merge anyway, it creates more bother than it removes.
I'm not sure where this sentiment comes from, could you elaborate on that
Because in exchange for removing the occasional real double post infringement (and really, how many of these have there been?), it means the complete loss of any control over 'update'-style posting. I've had multiple posts turn into godawful multi-layered monstrosities that are stuck that way until another person says something. GIR has had to resort to multiple account magic to do something otherwise relatively simple. Not to mention the way IP Board does it shoves the new post content right up next to the old one and won't even accept newlines before the text starts, meaning it then needs to be manually edited anyway in order to differentiate between them for any sort of clarity. I wasn't expecting andy to immediately go and turn it off, but I'm not complaining. I'm happy to do any extra busywork that would arise from this if you don't want to :v
GIRakaCHEEZER said:
I'm also in favor of the removal of the auto-merge. I think it might help us weed out some of the new spammier members faster, since they could actually accumulate warning points from double posting. If people can't be bothered to make the effort to not double-post, then maybe their posting quality wasn't all that great to begin with (there's a reason it's against the rules).
It was also removed in part due to this post:
Polaris said:
Anyway, I've a question or two to ask. If someone else wanted to start an LP here, would it be appropriate to make a mock account for the purposes of multiple posting, like LDLP? Also, what exactly is the image/post limit? For some reason I had it in my head that it was 32 images or so, and your latest update has close to 100 - a token of how unobservant I am, I suppose.
And since we don't really want people to have to make multiple accounts to make threads with updates without breaking the image-per-post limit, andwhy decided to remove the automerger.
I like the idea of having it as a toggleable option/checkbox, with it being enabled by default, but I don't know how feasible it is to actually implement that (we'll have to wait for andwhy's opinion on that).