I was wandering whether it will be possible in EB to reinforce a besieged city's garrison via ships, if the harbour is not blockaded. It would be a nice feature. Besides it could be possible to resupply the city via ships or something, thus making sieges longer (hey sometimes sieges went on for more than a decade!) , and enhance the importance of blockades - which is imho often overlooked.
I think these features would be both historically correct, more realistic and fun.