Of course historically the middle ages was a period of siege warfare (compare the number of sieges during the era to the number of field battles).
Castles dominated strategic thinking, in that seige warfare had decreased dramatically from the ancient era so it was very tough to take them by force, until primitive cannons arrived. But seiges were drawn out, starving the defenders into submission was the only consistently successful approach. Storming the walls was very rarely done because it inflicted hideous casualities on the attackers. If seiges were resolved by battles, it was more often the defeat of a relieving force making it clear to the defenders that no help was coming, leading to surrender. The realistic style of starving them out is quite boring, and its not much more fun to storm the walls when youre only facing minimal opposition - the outcome is never in doubt but it still takes 10-20 minutes to breach the walls, march to the central square and kill the 2-3 defending units. IMO, field battles are more fun and dramatic. Heroic last stands and waves of men at arms climbing the walls as rocks are dropped on their heads should be the exception, not the rule as it is currently in TW. IMO anyway.