Oh he's amazing in XML1. But in each subsequent game he's outclassed. In XML1, he's the tank, second only to Wolverine and right above Rogue, and that's just as a tank. His role is strictly tank, since Wolverine is more melee DPS. Emma Frost has some tanking abilities, since she has radial debuffs and her diamond form is a good buff. But she's a weird tank and doesn't work nearly as well as Colossus. Worst character in XML1 is Beast by a lot. He has few tanking options, no support options, his Xtreme is terrible (not as bad as Rogue's though), and his melee DPS, while his strong suit, is bottom-tier when stacked up to about half the cast. He fulfills no true role.
Thing is in XML2, Colossus is now the worst tank in the game with some support abilities and poor DPS. His role is dominated by Wolverine and Juggernaut. He has some support abilities, but in comparison to pretty much the entire cast (particularly Scarlet Witch), then he has no use. In MUA he was bested by either The Thing or Luke Cage as far as straight tanking goes. Since that's his primary role, he now has support, but again is bested by Dr. Strange, Captain America, and a good chunk of the rest. As far as melee DPS, he gets straight bodied by sooooooo many other cast members it isn't even funny. Then, they decided that with the Gold Edition, they would add Hulk as a playable character, who is literally just a better Colossus in every conceivable role.
And that's why Colossus is terrible, even though I love that big, Russian, tractor-punching, metal bastard.
I like it, and it seems like they're giving her something of her own. As far as I'm aware, it's the first time they've ever really given her mythos that aren't reliant on other existing properties (Green Arrow, Wildcat, etc.).