1. Is your idea logical? Yes
2. Could it be done easily? Yes
3. Has something like it been done before? Yes
4. Has this idea been suggested before? Yes
So obviously vanilla enchanting doesn't work, because with about 40 levels and an enchanting table you can make enough P1 books to combine and have a full set of P4 in maybe an hour. Custom enchanting is extremely expensive and inefficient. For HCF, there should be a compromise. The max protection level should be 2, 15 EXP for each level. Prot 1 = 15XP Prot 2 = 30XP. Since you can't combine because of custom anvils there would be no point in getting Prot 1, it's a waste of time. Everyone would just enchanting Prot 2 (Max) for 30 XP. And that isn't even including Unbreaking, Fire Prot, Projectile Prot. Instead of having P4 difficult to obtain or too easy to obtain, cut everything in half so it's in the middle. P2 Medium difficulty to obtain. This is a very popular idea that's on almost every HCF server. It would bring a new meaning to the PvP system, help balance HCF, and make the Economy better. It would also encourage people to play HCF more, since things would be more Balanced and not only donators or people with 100 hours a week to play can have P4.