NEW: Won't be of any interest to you guys, but it's still worth mentioning that I can now edit all bundle data on the fly. Previously I was limited to game notes and bundle notes, now I can edit bundle name, and bundle start & end date. All that's missing is the ability to create a new bundle, which I can technically do since yesterday when I disconnected Lestrade's bundle IDs from ITAD bundle IDs (no big deal, I'm just storing an extra bundle ID in the database.) So that'll come at some point.
This is all done 'on the fly', so it's very easy to use for me (no big complicated forms to edit like on ITAD), and I can give editing rights to volunteers, too. (I'm just saying, because Barter has many volunteers that add bundles manually using Barter's terrible interface (well, at least from the screenshots I was given earlier this year... Maybe it's been reworked since.)
Either way, you don't need to be a volunteer to point out any bundle issues... There's a very convenient 'comment' button on bundle pages. ;)