1) You can get sapphires
You can get amulets
Good offense mechanics (offense units come back after they attack)
2) Level difference
Needing of large amount of army to collect anything
The risk is not worth it (you collect 5000 iron but you loose units worth oh 500 000 iron)
Low numbers of sapphire hamlets (I had not seen sapphire hamlet for 1/4 of year)
Too low numbers and too long distance in which you can see occupied hamlets
3) At 100% I would do following
I would go back to system of Settlements, that you would not need large army to get resources. But I would keep the offense mechanic that you would capture it and offense would go back.
If you would be reluctant for this change then this could be done only to Food, Iron and Gold hamlets. Because of Amulets and Sapphires are unique they could remain as they are.
I would make better density of the Hamlets and would reduce your sight range of them by 75% srsly you dont need 50+m sight.
What I would consider:
Adding sketches hamlet. Could be in form of Ancient Library.
Adding units hamlet. They would produce units during the time. They would be divided into Infantry, Cavalary, Occult and Beastiary. You would be able to choose if you want offense or defense units, but not the type of the unit, it would be always lower tier (Pikeman not paladin, Knight not GL ...). Speed of production could be 1/10 of your production speed, but it would count in your speed ups (Skull runes + Dragon bonus + Relic bonus)
If you would not want that thing above, they could consider something like Obelisks of Power, if captured they would speed up building of your normal units by 10% and your Imperial units by 20% (that was only example, plarium devs would choose the exact boost by their calculus). That could also raise your income from sapphires.
You could add something like League hamlets.