You should also test Mount and Blade. Big scale battles, nice graphics, interesting stories and quests, lots of nice mods and overall "good". Ofcourse it and TES are on different islands, so to say. TES is a RPG, MnB is a medieval war′n′life thing... Or something.
Besides which Mount & Blade is built almost exclusively around combat, and one of its main selling points is the large battles involved. The entire game's design and its engine are both structured specifically around providing that sort of thing, whereas the TES series generally isn't.
That's not to say that this can't be done, but I really wouldn't expect it unless it's something they'd been planning from earlier on. Large battles aren't the sort of thing you can do by just tossing in more NPCs and expecting it to work.