Hello there.
One of the games I almost exclusively played at some point when I was young was Mindcraft's Siege (and I think the expansion Dogs of War). It is easy to find as of now on abandonware site if you wonder what is it.
Basically, the game was just a big Siege battle, and by Siege I mean the "assault" part, with several hundreds troops on the map and zounds of different units. No ressource management, no construction, only friggin' battle and strategy such as "Ok, I ll try to push the Siege tower there, so I can take this tower which would allow me to control the main courtyard, but before I ll need to draw attention on this side on the castle while my catapults obliterate the defenders".
I really loved the game, even though the attacking IA was so poor.
They made an "historical" Walls of Rome, which was fair as well.
Anyone knows whether there exist a more recent game with this concept (I tried Lords of the Realm 2, which was actually great and more beautiful, but there were still significantly less details).

While not exactly brand new, Stronghold: Crusader might interest you. There's also an Extreme version that lives up to its name as it's supposed to be pretty much impossible.
You can play historical battles in the Total War games. These include sieges, which are very well done on the whole. But you're not getting the most out of those games by sticking with the sieges. Still, it's a good starting point. If you play the campaign you'll be laying enough sieges to whet your appetite, that's for sure.
XIII Century completely focusses on tactical battles. No resource management, but not much in the way of sieges either. Which is pretty much the same story with Crusaders: Thy Kingdom Come. Both are recommended if you're interested in tactical battles though.