I constantly see very strong NPCs and monsters attacking me, even bandits are so strong... Do any of these mods make the game harder?

Skyrim.esm
Update.esm
Dawnguard.esm
more carriages.esp
AdventurersAndTravelersLight.esp
WiS IV.esp
WiS IV - New Equipement for NPC.esp
WiS IV - Perks for NPC.esp
DeadlyDragons.esp
WiS IV - Double ArrowDamage.esp
WiS IV - Werewolf & Vampire.esp
MidasSkyrim.esp
WiS IV - AI & Spells for NPC.esp
WiS IV - Realistic Combat.esp
WiS IV - Races.esp
WiS IV - Blood Coins.esp
Tytanis.esp

I would think that WiS, Deadly Dragons and, perhaps, Tytanis would make a game more difficult. My guess is that WiS is probably what's making your bandits strong.