The Hamlet deficiency
To be honest, Hamlets have become relatively useless for resource gathering, and are only viable for PvP and Def unit XP. I like the idea of having additional places to get resources from, but because the hamlets cannot be effectively defended, and the easy reward of 2 dragons for a successful attack exists, they can be occupied for only a very short while before someone attacks them. It doesn't mater what I put in the hamlet, from a few archers to a few hundred griffins, Someone ALWAYS wipes them out. I have been hit by forces of well over 15mil offense, several hundred leg units, 15k dragons, 10k wyverns...etc. Even using the "collect resources faster" boost is useless if you can't hold the hamlet long enough to gather a worth while amount. repetively sending in a couple of units to gather a tiny amount of resources quickly is very tedious and extremely inefficient.
The "hold a hamlet for 90 minutes" cannot be completed viably as things stand, maybe the application of a timer that is graduated for the size of the defending army in a hamlet that makes that hamlet unable to be attacked until that timer expires would be useful. For instance; 10 nomads can collect 6 saphs in 17 minutes and have about 2.5k def. If a timer allowed maybe 10 mins of collection time, then using the hamlet for resources is beneficial. similarly, 100 griffins can collect 144 saphs in a little over 5 hrs. allowing them 2-3 hrs collection attack free would make holding a hamlet for 90 minutes achievable.