I think the biggest problem I have with dota is that half their skills are fun and half of them are unfun.
What fun is an ult that just gives you like 40 agility passively.
Well, personally I really enjoy that ult. You hit crazy hard, it's pretty enjoyable and opens drow up to the option of getting an early HotD that is crazy effective because of the huge burst increase in damage you get from your ult.
Although they also made it a bit more interesting and have a tad more synergy with her set pretty recently. It now gives 20/30/40 agility that gets doubled if there's not an enemy heroes within 400 range of you. And her aura has been changed to give, at max rank, 26% of your agility to ranged heroes on your team globally.
But again, I've always found it interesting as it opens her item path up to some choices that similar ranged carries can't get as smoothly.
In terms of hero RNG CK is indeed the most significant by far, and pretty much the only one it can be a big deal on. It's really only a large factor at low levels though, particularly when its a 1-4 stun. You can draft well enough though in DotA that he never gets a chance to throw a stun in early game.
The biggest RNG in both games that I'm always surprised everyone seems to be content with is crits though. Even with P-RNG you can get some really fortunate crits that just win fights.