Instead of just X bonus for Y weapon against Z opponent I tried to come up with some perks which would give a bit of variety in the way different styles are played…
Heat Seeker (marksman 50?): Arrows fired at a long distance will arc (slightly) towards heat sources (works better in colder climates)
Best Buddies (conjuration25?): Using the same summon creature spell will level that creature up to become stronger (capped)
Triad (conjuration 60?): Allows the player to summon 2 creatures at a time.
Amalgam: (level 70? in magic field/s applicable): Spell making now lets you concoct spells with 2 effects, extra cost of magicka if different schools of magic are combined.
Call of the wild (personality 50?): Animals below PC level, within a 50ft radius will come to the player’s aid if attacked. (Excludes passive and diseased animals)
Arcing (destruction 50?): Shock spells have a chance of arcing onto multiple hostile enemies wearing metal.
Pickpocket (sneak 40?): Allows the player steal from NPCs who are unaware/sleeping/drunk/unconscious.
King hit (H2H/Blunt 50?): Instantly send an NPC to the ground if hit from behind and are unaware of player.
Doppelganger (illusion 40?): Casting illusion spells in combat has a chance of causing mirror images of the PC to appear confusing hostiles.
Counter (Weapon lvl 40?): When using a balanced 2 weapon style, successfully blocking with the main weapon has a chance to counter with a critical with the offhand.
Argonian Blood (Argonian, lvl 10?): Immunity to poison and chance to cause poison when fighting H2H or being hit from H2H.
Eye of the Jiit (khajiit, lvl 10?): Eyes automatically adjust to low levels of light allowing to see better.
Pyromaniac (destruction 50?): fire spells have a chance to set targets alight causing them to go crazy, fire can spread to hostiles who they come into contact with.
My favorite weapon/spell/potion (applicable skill 25?): regularly used items will be more effective/durable.
Telekinetic burst (Alteration 30? Since mysticism is gone): when being attacked and health hits 25% you send out a shockwave knocking over nearby hostiles.
Renown (personality 60? Decent lvl of fame, lvl 25?): Lower level hostile NPCs are less likely to attack on sight, unless they have a large numbers advantage. Also causes citizen NPCs to be friendlier.
Outlaw (high bounty): Become an outlaw, rob travelers, raid towns, access services with bandit groups. Many bandits become friendly, Guards become hostile. Disposition with citizens will drop, fear and compliance will rise.
They are just some ideas anyway, maybe good, maybe crap… feel free to edit or rebalance. Tc