You have two Hamilton Travelers, right, and are letting one go? I think there needs to be a distinction made between the original Hamilton (in soft leather and saffiano leather with chain/leather strap) and the new variations on the Hamilton (the Hamilton Traveler in vitelo leather, the top zip Hamilton in saffiano leather, etc). The original Hamilton is a classic in my opinion. The others not so much.
All are beautiful, but I think the original Hamilton is the one that people will be carrying for years to come. For those who think the lock/key will go out of style, that's what makes it a classic (aka Hermes Birkin dupe). The beauty of the Hamilton is that you can take the lock off whenever you want, and it looks like a totally different bag. Plus there isn't an MK logo on the bag, only on the lock, so without the lock it just becomes a beautiful satchel/tote. Or you can take off the lock, open up the belt, and carry it with the lock on the bare hook. So many options for this bag make it a classic in my opinion.