For all intents and purposes, it basically cleared my board and killed me from 20 health.
I'm really not sure what you think is a bigger tempo swing?
This is hyperbole. Owl didn't clear your board. Owl's impact was removal of taunt and deathrattle off a very powerful board control card. You're attributing everything to owl, ignoring the pre-existing highmane and the just played loatheb - both of which had a bigger impact.
Owl, itself, reduced the board strength of a single minion and allowed him to race you to death. That reduction in terms of tempo was about 1.5 mana and he played a 2/1 which is about 1 mana worth of strength. It's simply not a big tempo push itself.
Here is a stronger tempo push, from a single card. Black knight turns your belcher from a 5 mana into a 1 mana minion. It not only kills the front of the belcher, but it also plays a 4 mana minion. That's like an 8 mana swing, easily double or nearly triple the impact of owl in that scenario.
TBK has that big of an impact because the card in general just is not versatile. Reducing silence's range of impact, to say taunts (although I don't like this suggestion) is a way to reduce it's versatility. The problem with the owl is that it's impact is strong and wide, not narrow.
Aggro decks deserve tools to counter anti-aggro just as much as control deserves tools to counter aggro. As a heavy control player myself, I still agree with that sentiment. I also really want to point out that aggro hunter doesn't run highmane. You're playing a midrange hunter, or a hybrid.
Although, people lose to aggro all the time because Ironbeak makes Taunts useless against Aggro. You know, the one thing Taunts exist to counter.
Owl doesn't make taunts useless against aggro. Many aggro decks only run a single silence. And I ran way more than a single target they need or want to silence. And even when they don't have the silence, they can still win.
Ironbeak Owl is one of, if not THE, most requested nerf after Druid combo and has been since Hearthstone left beta.
UTH
Buzzard
dr. boom
undertaker pre-nerf
miracle rogue
leeroy jenkins
handlock
face hunter
zoolock
I mean, the list goes on and on. All these requested nerfing more than owl.