Indeed it would. If Syaoran became the master of the cards, instead of Sakura, he'd probably go back to Hong Kong to show that he accomplished his task while he was there in Tomoeda. Sakura would probably be disappointed and feel as though she didn't give it her all because she wasn't crowned the mistress of the cards even after all she went though. But, she'd most likely get over it and be happy for Syaoran.
As for the other questions.. I'll give my best.. answers for them. ^^;
What if the first card Sakura pulled out of the book of Clow was one of the other Elemental cards instead of Windy?
Well.. hm. She wouldn't have the ability to fly around in the very beginning and learn how to master one of the other elemental cards to the best of her power. ( sorry for the short answer.. :/ )
What if Meilin and Tomoyo had magical powers?
For one thing.. I don't think it would be that good of an idea. I mean, Meilin was rather huffy about the fact she didn't have magical powers but it made her character more likable somehow since her personality is so firey. She really doesn't need magical powers but if she did have them.. I bet she would gloat often about how she and Syaoran were able to sence the cards before Sakura could. Then again, she has already done that during the Big/Create episode.. ( only, it was more gloating about Syaoran, which she doesn't mind doing. ^^ )
As for Tomoyo, I don't know. Her personality is sweet and calm, and yet at the same time she'd passionate about fliming Sakura all the time and creating costumes for her best friend. She doesn't need magical powers, but if she did.. I don't know how she'd use them. I mean, knowing Tomoyo, she would much rather flim Sakura instead of throwing herself into the action with Sakura.. you know? That's just how Tomoyo is. ^__^
What if Kaho never broke up with Toya?
Then he wouldn't ended up with Yukito ( such to fangirls diappointment.. ).. but I'm sure Touya would still be willing to give up his powers in order for Yukito/Yue to stay alive later on. ( Again, Sorry for the short answer.. don't know what else to add.. )
What if Sakura never went over to Shaoran's house during the Move card episode?
Uh.. I have no idea. I haven't really watched that episode all the way though. I'm guessing Meilin wouldn't of started to yell at Syaoran for having two girls over. *shrugs*
Would Meilin had been so angry at Sakura all the time and would they had ended up being closer friends than they were in the show?
Maybe, then she won't be suspicious that Syaoran liked one of them and then she'd be nice to Sakura. However...when she finds out that Sakura is also collecting the Clow Cards.. she'd get angry with her about that and get completive (because she wants Syaoran to get all the cards and not some another girl she just met... )
But they were kinda friends, but not close. Since Sakura was willing to be nice to Meilin no matter how much Meilin got upset with her. It was that very reason why Meilin ( although very disappointed and heartbroken ) was willing to let Syaoran be with Sakura.. which I think is very sweet of her and shows that she too, cares about Sakura as a good friend.
Kewll... --;