The smallest change you can make to make a champion OP
You have to make a change that seems super small, yet makes the champion very OP.
For example: 
all soldiers stay alive within range of him
77 Comments
Silence restored.
Silence restored.
Move Quick bonus not lost in combat.
Only three stacks of Concussive Blows required to stun.
Has a real weapon.
Poppy gets 200 more base mana
E - Event Horizon: Veigar twists the edges of space around the 375-radius target area for 3 seconds, stunning enemies who pass through the perimeter and inside the perimeter for a short duration.
Gold items now stack...
welcome back 
Just take away the 25% part of his passive:
Singed gains bonus health equal to his mana.
W shield does not have diminished healing.
Passive is a trinket
Passive is now any unit
Passive now is any unit
Each of 
's three talon strikes are all knockups.
can use consume on champions.
's Q cooldown is refreshed if it hits a minion.
's turrets all have the same aura as his passive.
Garen slows enemies caught in Judgement.
Ult resets every time he uses it, regardless of whether or not he gets a kill.
Now gets AP for last hitting minions and enemys with all his abilities
Blitzcrank's ult passive now only targets champions.
Mantra'd Q now explodes at cursor location, instead of exploding on the first enemy hit
Minions/monsters no longer give reduced shield generation
Ultimate can be used while in mini gnar
Raise Morale gives nearby allies the full buff, instead of half the buff
Toxic shot counts as spell damage
Soldiers apply on-hit effects as well as spell damage
Passives stack now
Vayne's Silver Bolts now proc every two hits instead of three.
Passive has no cooldown
I can't imagine if Akali had a spellvamp passive. She would be so broken.
Vlad passive stacks with itself.
at level 16, nothing stops his bonus hp regen
Man, some of these people's "small" changes.
q has a longer range
Passive:
Nearby enemies have their Magic Resist reduced to 0.
Widen the hitbox on minion projectiles launched by Sion's E.
Passive regen is 0.1% HR Per Lv Per Sec.
is now ranged
's Q can now Crit.
You can perfectly steer Sion's ultimate.
's charm does not affect minions. (goes over them)
does not leave stealth in combat! :O
throws grabbed minions back at enemy champs dealing damage equal to remaining minion HP.
100 Range increase on all spells.
R now gives 10% life steal while in use