Suggestions for new content in SK:
Positive Status:
There exists already curse, poison, fire etc. that can all kill you, however, nothing that actually helps the player. Some examples of positive status' would be:
Increase Attack/Def: Increases attack/def by 50% or however much you might want for however long, say 30 seconds or something.
Regen: Restores 1% of health per second for 180 seconds
Haste: Doubles movement speed for 20 seconds, basically the opposite of stun.
Invisibility: Self descriptive, deactivates for 3 seconds or so every time you attack or take damage.
Invincibility: Self descriptive, 10 seconds of being untouchable
Rage: Increase attack, defence, movement speed, attack speed, charge time reductions etc by 10% for 30 seconds.
Those are suggestions for status' that do not kill you. They would most probably be induced on the player by a vial or whatever brilliant idea exists out there somewhere.
Proximity mines:
A bomb that explodes only when enemies enter its blast radius. Laying down another while it is active will destroy the first one without it exploding.
Deployable gun puppies:
Or something else that can stand there and shoot for you for 20 seconds. Could also be a deployable love puppy. Ideal for defence.
Snipers:
A gun for players that is single shot, has very long reload time, can allow a player to see beyond their normal field of vision (the scope), greatly reduces movement speed while in use and of course: does massive damage to a single target.
Spread defence shield:
A shield that defends against all the elements, but with only a quarter strength compared with regular shields. Applicable to armour and helms.
Hope these suggestions look appealing.
Knights need no more buffs, the game is already too easy.
Battle Sprites are coming out soon that will do similar things to what you've suggested here.