Yeah that is a bit overboard but it is so much quicker to make money in the mainland. You would save so much time just leaving Haven
This is it in a nut shell.
There should be way more opportunities in the main land than haven. Even if players do try to take advantage of Haven, at some point they should be better served to go to the mainland.
But if some people stay in Haven and build up I really don't think it will have a large effect on the over all game. For every little bit that is being done in Haven there is a whole large world where much more should be getting done outside of it.
If it turns out not to be the case then I think the problem would be with the opportunities in the game itself and not that of Havens.
That all being said, I do agree that they should make it where you only keep what you can carry and are not allowed to be encumbered when you transfer to the mainland.
Getting access to a whole banks inventory in every town is quite a stretch from the normal workings of the game. I can see how someone would want to fill this bank before leaving Haven to take full advantage of it.