I received that same kit as a gift from my SWMBO, and I was not overly impressed with my first results on the GB Pilsner or Aztec Cerveza either. But when I tried Mr. Beer's Oktoberfest and American Ale, I was hooked. Don't give up too soon, Snuffy. The GB Pilsner and Aztec Cerveza can benefit from additions (I like the Fresco Chile Lime recipe using the Cerveza), but they have many other refill cans (especially the Craft series) that taste great on their own.
I have been cold-crashing from the beginning (this was my 17th batch), having read RickBeer's excellent explanation (find one of his posts and look in the links in his signature). I have never had any issues with carbonation, but then again, I have never gone this long fermenting before, and this is maybe only my 3rd batch with S-04. This one ended up at 25 days fermenting, then about 36 hours cold-crashing. Hopefully it will carb up fine, but if not, lesson learned. I am not really concerned with hazy beer either, but I do like getting the trub compacted and solidified, which helps get more beer out of the LBK.
This is an interesting read on yeast metabolism that might be relevant. This site is a good source of info about beer making in general.
What I got out of it was that it would be good to include a nutrient that includes dead yeast. I had read that some on the forum do toss in an old pack of dried yeast for food, so this may be a help - and a good use of old yeast. (I have a lot)
I will also throw in this link - another interesting read.
Only my very first (CAL) attempt out of about 15 tasted a bit like cider and that was when I just about did every thing wrong in the process (not keeping great track of the fermentation temperature, disrupting the trub while in the LBK and in the bottles, etc.) Even with that, the beer was "ok" -- certainly drinkable. Out of this 1+ year experience with MrBeer, that's the thing I'm happiest about--and I know one day i'll brew a "bad" batch for whatever reason--but, if you follow the directions and the common advice on this board, you'll find yourself with at the very least drinkable beer at the end of 7 weeks.