Well I think it’s more of a mistake to pre-order a game the same day it’s announced, months or years before the game is actually released. If you do that, you’re not guaranteed a game, and you may not be able to get a refund once it actually comes out.
Usually it’s safe to buy a game right after it comes out, because you can always get a refund. You could have bought it today and played it just to try it out, and if you didn’t like it, you could have gotten a refund.
That’s what happened to me. I bought this game today right after it came out (no pre-order) thinking it would be Warcraft 3 brought up to date. Well I played it and was severely disappointed. There were so many issues that I ended up getting a refund.
This other thread I created lays out all my experiences, so you can see what buying and playing this game is like: Launch Day Gameplay Video Showcasing Bugs and Errors