I don't know how to make maps and never did... but I handed over the money with no hesitation whatsoever. And I don't regret it.
I would've, yes. A map editor is not the central point of the game, but an addon. It's like saying would you have still bought the cookie without chocolate chips? Hell yes, a cookie is a cookie. The chocolate chips are just a sweet, sweet addition. Now I'm hungry.
Complete answer: Campaign:I usually only play a campaign through once, and I wouldn't necessarily bother to complete it. Maybe around the 2/3 or 3/4 mark I'll get bored of it. Player vs computer: I like this because it's something I can master and experiment with. Online multiplayer: We only get 50% wins, which is not mastery. I'm not particularly fond of competitive games either. If I do online play, I prefer cooperative vs computer. LAN: Editor: The editor is important for me because I am creative and interested in game development. Editors give a lot of insight into how the game works. I will typically make a few melee maps, and then experiment a little with triggers and object editing and make a dungeon crawler of some kind. Depending how successful that is, I may make another. If there was no editor, I'd be much less likely to purchase the game. Certainly, I'd not be willing to pay full price.
Yeah, I'd still buy it. That said, I think the editor is really important especially for online play. I was never good enough to compete with most players in default maps on battle.net for SC1, but always loved seeing what people could come up with in the editor. Blizzard would be silly not to include it, since the fans can build some really awesome and creative games with it, making online play more fun without any real extra work on Blizzard's part. Also, I have fond memories of the SC1 editor as my first attempt at anything resembling computer programming. Triggers are just logical statements, and I remember years later when I learned actual programming, thinking back to the days when I was fiddling around in starcraft. We wouldn't want to deprive the next generation of gamers of a chance to start getting their hands dirty learning how to make computers do stuff! Think of the children!