As has been mentioned, this is really a good idea for that range of games from the early to mid 90's, when the Amiga was often the graphically superior machine, or just had better versions of games that also came out on PC at that time.
Space crusade is one example that springs to mind:
http://www.mobygames.com/game/dos/space-crusade It's a dog of a game on the PC, but the Amiga version i'd sink untold hours into playing hotseat with a mate. This is just one example of where the amiga version of the game was superior to the PC version, but around this era you found this quite often.
Once the 486 came along the pure CPU power of that compared to the Amiga, and the better graphics display of SVGA cards pushed the Amiga to extinction (as a games machine). But for sure there are quite a lot of better Amiga versions of games that also came out on DOS.
If this does become an option for GoG, i'm sure previous Amiga owners like myself can provide a list of titles to look at.