Development suggestion: Second Barracks and second Provisions house
I haven't read all 110 pages of this thread so hopefully my suggestion has not cropped up before.....
Allow a second barracks at say lv45 and a second provisions house at lv50.
Reasons: By the time a player makes it to lv45 they are working an adventure and then having to spend a day or two rebuilding the troops in order to move on to the next adventure. This gets boring and high lv players leave. By speeding the troop replacement the player stays interested and active. Likewise the extra provisions house (and that shouldn't be before lv 50 - reason below) means that the player can finally make enough settlers to go with the troops they are producing, again it engages the player and keeps them active.
Benefit to bb - and there has to be one or this will never happen
The extra barracks requires settlers to be turned into troops so more noble buildings will be needed, this either requires licenses (gems) or deeds (gems). The provisions house won't necessarily be able to cope with the constant demand for settlers (nor may the players bread supply, 500 settlers a day requires bread supply at 6.5k/12hrs - that is 8 lv5 bakeries with their infrastructure and storage for same) so more settlers need to be bought (gems).
By lv50 and the new provisions house the player has probably run out of the backlog of adventures stashed in the star menu so now they need more adventures (gems). The players are possibly getting irritated at never having enough bread as the farms need constant attention - silos (gems). Water keeps running out - watermills (gems). And I haven't even gone into the mechanics of producing enough weapons!
So you see this works on many levels - for those who posses immense patience and who are prepared to spend long hours each day repairing and replacing on their island there doesn't have to be any cost but for those who want the benefits without the hours of work - looking to set things going and come back each evening to do another adventure without the maintenance hassle there is a gem route for that.
I hope this suggestion meets with favour - I'm only lv32 atm but I see high level players getting disaffected and leaving, this can't be good for the long term. It would be nice to think that bb are looking at how to extend the game beyond lv50 - though that does, I think, present problems in terms of what else may be farmed, mined or sought in quest without having to do a full recode of the map with all the problems that could/would cause. Hopefully my suggestion can provide enough interest for high lv players to bridge the development gap.