"More stealthful than the night"
Official ESL Gaming
Cabrakan literally has all of that, his 1 increases his base movement speed by up to 35%, makes him immune to all slows/roots for 5 seconds, and does a ton of damage, along with making his first basic attack stun whilst under the effects.Thing is with cabrakan is his base mobility is bad, no great initiate or escapes. His 2 works but since he'd be squishy its tricky. Anyone with a leap or and kind of speed up gets away pretty easily. In casuals he could work but lacks to much at a high level.
Ymir works because he has his great stun. High damage 2, and both apply his 100% damage passive. Then the high damage crippling ult to top it off.
His 2 will also stun once he takes 5 hits, which he's going to in the form of minions or basically anything else, which will stun in an AoE if anyone is nearby, and also hit for a chunk of damage.
His 3 will mop up anyone left alive after that, whilst also applying a really annoying effect to anyone hit by it, and his 4 does damage (unlike Ymir) and can wall things off just as easily.
Theory fighting I know, but can't see any realistic reason he couldn't be good at it.