Fixing Ms. Smartypants.
First of all, most of the characters are written wonderfully. Seriously. This is some of the best "normal" Applejack writing I've ever seen (exactly the right levels of stubborness, caring for her family and trustworthy to a fault), and the Rarity writing rivals that of The Romancing Quest (hopeless romantic, basically). The CMC are also quite nicely done.
Second of all, the foundation of the story is nicely established and quite nice. Mac took Smartypants because he has a crush on Twilight. Applejack tried to set Macintosh up with Fluttershy because of how similar they are and how easy it would be to move Fluttershy into SAA. Macintosh gave it a shot, but she liked him too much to lead him on because she just didn't like him that way. Applejack doesn't take the hint because she thinks Mac screwed up, and tries to confront Fluttershy over the issue (and that's where the first chapter ends, more or less).
Overall, there is a really good chance for a really good story there.
However, I have two problems with it (one minor, one potentially major):
I'm not a fan of a specific aspect of Mac's character in this. Namely, he is the strong, intelligent, reserved guy he is usually portrayed as; but he is reserved because he has a speech disorder rather than just because he only speaks when he has something wise to say (to the extent that he takes speech therapy classes with Ditzy. Also, this is a "Derpy is an insult" story, but it isn't milking it for cheap drama as far as I can tell). I may be able to shake this, because there is potential for real character development there.
The other problem can be summed up in 4 words:
Cutie Mark Crusaders Matchmakers.
In my experience, even when they are done well these are basically straight up idiot plots (albeit justified ones); and the only reason it didn't bother me when The Romancing Quest did it was because it was a comedy first and shipping second and it milked it for all the former could get out of it. I still think the story can be really enjoyable, but I want less "CMC screwing things up" (they've already misinterpreted the storyline as being TwiJack because Applebloom is just as stubborn as AJ in trying to force the FlutterMac, and decided to hook Dash up with Rarity for the lulz) and more "actual story progression."]