They shouldn't have taken them away to begin with. Most people don't want to buy something, earn it ingame, just to turn around and need to re-purchase the same thing again, and on top of that, need to "earn" the damn thing a 2nd or 3rd time.
That happens in many games, though. Halo 3 had loads of armour that had to be re-earned in Halo Reach through different means. Call of Duty has people re-unlocking many of the same weapons through every release. Monster Hunter requires you to re-build weapons and re-level characters that people may have put hundreds of hours into with every release. This is not a new practice. There is no problem with re-earning 6 weapons when there are so many new ones.