Try vampire lord, whis -460 armor, good base atk time and 50% life steal it is easy to kill forgotten one and death hood. Easer than whis illidan bcs lord is just a better illidan (best armor red in game (but can be dispelled)) 10% more life steal, more crit and eva, more atk speed and +280% dmg from base dmg. He's so powerful that I didn't need Sinister Edge to kill these bosses.
Depending on your goals and the easyness you are looking for I would Say:
- Illidan is the most confortable to go, if you want to beat death ice Wolf and the one After byatis forgot his name. Not saying it s easy to beat them it's still endgame for a normal solo game but you don't have to do complicated stuffs
-Satyr and Dante are a little harder to start with but if you manage the start they are a little stronger solo options in my opinion with the same style or play. Never soloed Michael personnaly but those where my closest tries with him having less than 1/6 of his life. Satyr is also the easiest to kill deathood solo.
-But for my best results thrall and necromancer are the only ones i killed kelthuzad solo, and satyr deathood
And it's a good call to watch Skinnergabriel videos but don't forget most of them were before the holyitems