The more I think about this the more I think (read: know) that this will cause issues between scanlation groups. If some group subscribed to the forum picks up something that a group that isn't subscribed to the forum had picked up before it was suggested, the users/subscribed groups can't just go "oh well, you're not subscribed to the Batoto forum so it's your fault and/or you don't have the right to do it."
Also, it has another issue: slow releases. For instance, my group "Orinjido Scans" releases some series very slowly, but it's not because we want to: there are valid reasons. Reasons that we post on our site and tell people in IRC when the release gets delayed for a large amount of time. And we have no intention of dropping those series.
Alas, readers won't be so understanding when they have a central place to ask for series to be scanlated. Just ask Derek, he can probably tell you how many times a series from my group or another group that are still actively being done, just slowly, gets requested and how often they COMPLETELY IGNORE the reasons that we lay out for them.
We can have members check MangaUpdates for scanlating groups before placing a request. In fact, make it mandatory to link to MangaUpdates info page so we know that they "at least tried" looking for groups scanlating the series.
If are already working on the series, you just mention it-no need to give reasons. Then the thread gets locked.
Members will be (hopefully) checking for previous requests so when they see the thread, they know that it just a "slow release" and not dropped.
If it gets requested again, it will be considered a duplicate and deleted.
Groups don't have to entertain any further similar threads.
So yeah, good idea on paper but too many problems with the actual implementation.
P.S. I'd like to make it known that some scanlation groups actually oppose Batoto (as they do other online readers), so making it a requirement to all scanlation groups to subscribe to a Batoto thread just to keep people from stealing your series is... not good...
Like 101010 said, participation is completely voluntary. It would help that all groups participate-but that's the ideal scenario.