Solidus, heroic and evil, an excellent Kojima villain:
I actually think Solidus is the most heroic villain of the entire franchise, being the most noble in goal over every other, unless you really ever considered the Boss as being a villain. However, excusing of his past sins is not a good thing, and saying he is "nowhere near as bad" as any other MGS villain is ignores too much of his past to be an accurate statement. He really is Big Boss but less extreme, but that still includes "1. Kill parents 2. Adopt children and make into soldiers 3. Make them kill more parents, see step 1. 4. Rinse and repeat" as a central manner of action in his past, and there's no indication he feels any remorse for it, so continuing this trend in likely to have occurred in the future, had he reached his goal of disrupting Patriot control and lived on to fight for his own ideals.
I even watched and really liked that video you've linked, but Hyper Bit Hero's excuse for Solidus' hideous war crimes is pretty lame. Saying it was just "poorly executed" and was only an awkward moment is astounding, and really misses the depth of the character. It reduces the complexity of the character and really makes him too sympathetic for a Kojima villain to just say "Oh, but he didn't mean to turn Jack into a serial killer." "Oh, Kojima just made Solidus say he killed Jack's parents so the player would be motivated to kill him, he didn't think about how evil that would have made him.". No. Solidus told Raiden he killed his parents because it made the coming battle all the more thrilling for him. He killed Jack's parents because he wanted to see if he could manipulate Jack into becoming his "son" through only his memes. He considers both Jack and himself to be monsters made by man, and willingly forced Jack into that life.
Solidus is one of my favorite villains in the entire series, I was pretty disappointed he didn't show up as a cynorg in MGR, and I'd be saddened for us not to get more of him in MGSV before Kojima can no longer add to his character, but please don't excuse the fact that he did just what Big Boss did in the past.
(Sorry for moving my reply to a new post instead of leaving it as an edit to my earlier one, just didn't want to get left being on the new page.)