It’s been a long time since illidans last rework , (the new rework in 2019 was NOT a real rework at all)
lets See why illidan needs a rework 
He is very pve (Player versus environment) oriented hero and excels with it quite well. Although his pvp (player versus player) fighting skills are a bit lacking. He mainly needs buffs to be more useful in 5v5 fights.
At lvl 4 Unbound:
(Sweeping Strike can go over walls and terrain.
❢ Reward: After hitting 30 Heroes with Sweeping Strike, gain a second charge.) 30 Heroes is a lot specially with his low health 
it should be 15 heroes to be more balanced.
his 13 needs some changes : Nimble Defender
(If Sweeping Strikes hits an enemy Hero, gain 25 [Armor] for 2 seconds, reducing damage taken by 25%.)
the duration should be 2.5 seconds , because illidan is too weak in 5v5
if his lvl 4 ability (Unbound) is mixed with (Nimble Defender) at lvl 13 Illidan will be more effective in team fights because of his low health.
His lvl 10 needs a complete rework
(Metamorphosis) Needs to be His Trait !
its main use is for dodging pyroblast (kael’thas lvl 10 ability)
and due to it not being picked in many games because it has no use till lvl 20 : (short duration , no att speed , no mounting , and low health increase ) muridan Avatar is WAY better !
(Transform into Demon Form at the target location, dealing 46 damage 
in the area. Temporarily increase your maximum Health by 220 
for each Hero hit. Lasts for (((18))) seconds. LOL)
if you are lucky you can hit 2 heroes!
“if the enemy team has Samuro and the lost vikings (it will be 8 heroes) 1540 at lvl 1 (1717 HP + 1540 = 3257 like Blaze in lvl 1)”
wow that’s a lot.
Having a lot of thoughts about illidan
we think Metamorphosis must be his Trait like Alextraza Dragon form !
So pls replace his lvl 10 abilities!
Don’t let illidan be forgotten
<3