I would say that part of your problem has nothing to do with Uplay/Amazon, but rather your poor net connection. At least in my experience, it's never taken more than an hour to download a full game from Uplay. And that includes some of the Assassin Creed games (at 9 gigs a piece).
While you may have a valid issue with the patching process, even Steam with it's new content system now takes far longer to patch than it did with the old system.
Why does it take people so long to download things? Im living in a farm land area in the uk and a 10gb download only takes 2 hours.
There should be a study done to see why certain gamers have such problems because after all these years of using steam etc I have never had a problem with anything that wasn't my own fault.
Different net connections provide different experiences. The issues with downloading can be caused by either end. I've experienced download speeds of 12 kbs from Steam in the past as a result of my then poor net connection and their poor content servers.
Valve then improved their content servers and that speed jumped to 500 kbs.
Similarly, I used to get really poor download speeds from GamersGate due to their poor content server set up too. They have since improved it, but appear to throttle downloads as I never get above 5 mbs.
For the record, my current net connection is a fiber optic 1gbps one. Any slow speeds now are as a direct result of the server set up I'm downloading from.