I have to disagree with the BA thing. I'm a firm advocate for taking time and staying put in an era while you work on things for every where except Bronze.
When you finish the stone age tutorial you are then put into a bronze age hood. You don't know a whole lot about the game yet. When I made my beta city I knew the game but sure enough was attacked relentlessly in BA. I knew it would get better as I built myself up. How is a brand new to the game player supposed to know that? They don't so they quit.
We have hours old cities and players being attacked by bronze age veterans. I support everything this game does to limit the staying in BA. It does not make any business sense to foster an environment where fresh out of the tutorial people are being turned away from the game.
I'm sure not every person lingering in bronze is a bully and there just to kick the teeth out of the noobies. But I can see zero reason the game should encourage it.
But Inno is not encouraging players to stay in BA (or any other age). But the play experience in BA should be similar to all other ages.
And where do you base your assumption that people that stay long in the BA do so in order to plunder other [newer] BA players? Do you have statistics to back it up? You say you were attacked when you started in BA on beta. I wasn't. It is not meaningful statistically to just generalise your own experience and conclude that not only that is the rule, but to somehow guess the player's goals/motivation for doing so.
I dislike plundering (badly thought-out game mechanic, Zeus-CoA-CdM boosts count for the attacker but not the defender, of course the attacker does not bother having Deal-Basil so why should the defender be expected to?, the AI behaves stupidly targeting the rogues, and it is not possible to get 'revenge', as even if you beat the attacker in battle you do not harm them in any way unless you can steal some of their goods, and that is completely based on luck/timing.)
However, plundering is a part of the game and allowed by the rules. And it is just as bad when people do it in later ages. As for the new players being put off, they can very quickly move off BA and progress to IA, and won't have the BA 'veterans' in their hood. They will have the IA veterans instead and will be plundered by them instead. So no, I do not think that players should be discouraged from staying in BA if they so wish. There is already a major disadvantage of being in BA, that you cannot donate fp to other people's GBs. That makes many people progress to IA and camp there instead.
(If you want some extra protection for the very new players; then they could have what is common in other games, where when you start you cannot be attacked for x days (eg 1 day, or 3 days, or 1 week etc). But suggesting to somehow discourage/force players off BA to protect the newbies, is to throw out the baby with the bathwater.)
Many players have more than one city, and try different strategies and challenges in different cities. And by challenges it is meant playing in a way that is not efficient (hence the challenge) Eg Build all GB's (even the useless ones). Have a tiny town (no expansion). Stay in BA. (and try to get GBs without being able to swap, and not even being able to buy goods for FP). Now that is a challenge. Some may do it by buying lots of diamonds (something Inno would approve of
but that is not much of a challenge though.
So why should people be discouraged from staying in BA if they so wish? BA is the best age to do recurring quests actually (where if you are patient enough about clicking endlessly you can also do quite a few of the recruit units RQs within an hour; Let alone the blacksmiths, collect supplies, collect coins, the latter of which can also be done by guild-hopping).
Others stay long before they want to collect Zeus and Babel prints. Some may plunder while they are there, and yet some others may stay there mostly for the plundering. The point is, that the reason why some people want to stay long or forever in BA, does not matter. They have every right to do so. (and btw they should be able to donate IA goods when quests ask them, or change what can be donated so that BA goods can also be donated. Yes they are not needed for GVG. But that was the initial and outdated reason for the guild treasury existence. AF and OF are also not needed for GVG but can be donated).
As for something else that was mentioned earlier on this discussion, players having arrangements in different worlds (you help me in world A, I help you in world B), that is against the rules as has been stated, because this mostly consists of the secondary/helping city staying in IA and donating their fp to their friend's GB (or even to themselves when they have more than 1 account per world, again, against the rules). But notice the *stay in IA*. The 'helping' city only progresses as afar as needed to donate FP, ie IA. So actually all the 'advanced' BA cities are innocent of this. They cannot be existing just to help out another account/friend, since they cannot donate fp to other players.