Back in the early days, before there were over 1200 packs, there was quite a lack of content. Several contributors thus concentrated on quick content for many performers rather than in-depth explorations. Don't think badly of those pack creators! They performed a valuable service!
I think all of them would encourage you to flesh out their packs, though. (Personally, since I tend to download everything, I would prefer that if your new pack takes a file from another pack, don't rename it. If you do, my storage gets strained by yet another duplicate.)
Other than that, go nuts!