Best subcategory to ask this on would be PC gaming, just above the Hardware and Software link. But I suppose you're right about mods being software. One good mod for combat that I think should be used by everyone is the Locational Damage Mod. It lets you configure how much damage you do depending on where you hit someone, and with what weapon (be it a bow, blade, or magic). Ultimate Combat is basically a revamp of the vanilla Skyrim combat. If you want your game to be really realistic, Realistic Damages makes everything do a realistic amount of damage, with even an iron dagger doing 53 damage. Definitely do not use if you are not that great at vanilla Skyrim combat. If you are going for a realistic playthrough, Scientifically Accurate Unrelenting Force makes the Fus Ro Dah shout scientifically accurate according to the modder's math. To give you a sense of how powerful it is, I once shouted three guards over Dragonsreach. As for immersion, there are a few mods on the nexus that make magic look very good, and I am pretty sure that your computer is more than capable of handling them. There is the Important Information Overhaul. It has a really bad description, but basically what it does is makes your vision blur from swinging a sword to much or running for too long, makes it go red when you're low on health, and makes your vision go black and white when your magica goes down. Enhanced Camera allows you to see your own body, arms legs and all, when you look down in first person view, and also includes many first-person animations for things such as working at a workbench, mining, chopping wood, mounting horses, etc. Those are just a few that you might enjoy. Sorry if they're not what you are looking for in mods, but I'm sure that you'll get way more suggestions on the PC gaming subcategory.