I hope that you remove CD for +materials VERY quickly beacuse you lose players(Many new players are here only for look on 2,5D models, but i think that you lose old players, if you want that ...)
crafting rockets gives epic 60 experience, and small timeout - 55 min.so...
If you want to make enemies, try to change something.
Its an option, we will see how it goes. If people want to abuse the cumulative timeout by switching alts all the time its as easy to do with 20 minutes as it is with an hour, so revising it upwards is an option - based on feedback after a bit of a longer run of how it is now.