| Lastly, any reasons I should put the campaign on hold and play random map games first? |
My opinion on the campaigns is that they aren't the heart of the game. The true heart lies in the 'sandbox' mode, which is by far more enjoyable to play (IMO) than the campaign. Also, since the campaign scenario's are 'scripted', you can't truly get a feel for the game mechanics and strategies unless you play the sandbox mode. I don't know about anyone else, but I believe I've seen a few posts from some seasoned veterans regarding the sandbox vs. campaign modes... and all the vets chose the sandbox for maximum replay value and gameplay options/strategies/etc.
So in essence, cut your teeth in the sandbox and once you learn the game pretty well, try the campaign if you want to. I think you'll find more fun in the sandbox though, but at least you will have the skills to complete the campaign if you choose to do so.