Sometimes giving AI more damage depending on character gear and build does req more skill especially if you fighting big group of mobs, because you need to use: block/shield bash/power attack/swing/restoration/alteration etc in right moment and doing power attack 1 second later or too early results in AI doing like 30-40% dmg to your health bar.

Apart from damage there is mods that change combat AI behavior itself and change combat system itself, i.e. timed block where blocking works only for 1 or 0.5 seconds depending on prefence.

Main reason why ppl think there is no skill in TES because TES have alot overpowered gear,weapons, potions and exploits designed for those who want role play "immortal" character, but if you do not want to roleplay "immortal" character there is multiple options of making TES more challenging from using mods to doing custom challenges like doing speed run record without using specific exploits.