About the design standpoint I'd like to quote
this.
And seriously, I don't get your point. Why does it stink? If you had to unlock a map before you could enter a new area with stronger enemies, wouldn't that solve your problem? Actually, that was just an example. There are endless possibilites to solve abusing. And actually, it makes alot sense to me, because unlocking more complex and stronger monsters, not necessarily stat wise, but certainly player-skill wise harder to handle is by far the greater accomplishment. I've unlocked myself another greater challenge, in other words, fun. Just being rewarded with a digital item that makes me get advantages, hence making the game easier is what stinks of poor design.
Games are supposed to get harder the more you move forward, not just being able to do 2500 damage instead of 25 and having 10000 HP instead of 100.