With Rogue, if the stars align and I get off sweet combos and fancy plays I win for sure, but how often can you make those plays happen in Arena where your combos are never guaranteed.
I mean, it's not like the combos are hard: Play a card and then play another card. The only requirement is actually getting things like Deadly Poison, Backstab, and good cheap cards in the draft but that's not necessarily all that rare. Playing a Rogue is about making better board presence plays for 2-3-4 mana than any other class in the game can ever do. And, on top of that, they have the only Hero Power that can impact two turns in a row (and with charge) for only two Mana invested.
Rogue isn't really all that different from what most classes will do but they just have better ways of dealing with your opponent's early plays. Like, Bomber killing the opponent's two drop for free? That's the level of tempo Rogue cards try to add at the cost of card advantage.
But as a hunter at higher ranks (low teens) there have been PLENTY OF matches where I never had a chance to use it effectively. I'm actually thinking about removing it after getting past the noobs this time around as I'm thinking there will be better options for both control and aggrieved decks as most mid-level skill and higher players at this point run low minion counts on their side to not open themselves up to it. Or run high minions as long as the are 4 hp or higher.
There's like nothing more effective than it even at just a two dog summon. That's still two cards drawn, up-to 2 minions killed or two targets that need to be removed. Waiting for massive UtHs is just bad play generally. Take the incremental advantages as you can.
Piloting Hunter is a lot harder than most people give it credit for, especially when you get to the high ranks. There it's a test of seeing how well they know their deck and draws and how the match-up plays out. Like, how to squeeze out 30+ Damage given X mana and planning the turns out accordingly.
Like I said I don't think it's op, but you seem to forget that UTH often does one or more of the things I listed. And if the opponent is playing around it every turn it's already acting as an exceptionally strong card.
Every class has something you're playing around basically every turn. Hunter's thing is an entire chain of gimmicks around UtH as a piece.
Really, if anything of Hunter is really powerful to their gameplay, it's that their Hero Power lets them get away with this kind of play. Geting to ping guaranteed two damage every turn while waiting for a combo to deliver gives them a lot of leeway in terms of draws. As good as UtH can be seen as a multi-function draw, removal, and damage tool, what actually lets them do this is the inevitability that their Hero Power provides.
Edit: Not to say to nerf their Hero Power (because uh... how?) but just that having consistent reach like that is what makes things like this work. Besides that, the strength of their traps / the fact that every class just has to facecheck them really benefits Hunter immensely.