If you "fail to see" how unlocking multiplayer boosts offline - that you will later use against other players - is unfair, then I don't know how else I could rephrase it. But alright... Consider this: there was this whole uproar about the game being pay to win - that is, you unlock everything by paying, then use this stuff to destroy everyone online. Now, making everything unlockable in an offline mode would essentially mean the same, I'd complete every single challenge in a week by destroying some thousand useless bots, buff my favourite class to epic level with a fully upgraded weapon, and destroy you in multiplayer all the same.
But I am really tired of typing this again and again. Your complaint that singleplayer content should have been added to the game is totally valid. But merging challenges and unlockables is just simply a bad idea. Of course you should have access to everything offline, but keep that stuff there.
