It's not an idea to be instantly dismissed, and I don't think you're the first person to suggest something along these lines as the idea does seem familiar.
Personally, I'm not a huge fan of the idea since it will reduce activity across the forums that are already lower in activity than what they used to be, due to the rise of platforms like Discord etc. They're not dead yet, though!
While I see your point that it may cut down some shorter, "reaction-like" replied - they're still words and posts which, as I say above, we'll lose due to it being easier for someone just to tap a reaction instead. I don't know about others, but seeing (albeit short) replies like "hey this is looking great!" a few times instead of a like counter would mean more to me on content I created.
But yeah, they're my personal views on the idea but it would be interesting to see if there's more support from this from users/forum mods/staff etc.