I never got to play full power razakus, just played against it and i don't think that it would be that problematic to have it unnerfed. Wild aggro decks are strong ebough to kill it really fast. The wild powerlevel is so high, that it wouldn't be a problem, imo
I can name 10 other cards that can also be unnerfed which won't impact the meta much, if at all.
The only reason you've given is "so people don't have to play big priest if they want to play priest", which they don't.
Control/mind blast priest is a good deck. Inner fire /divine spirit dragon priest is a great deck. Razakus priest is a good deck too if you can play it well. Only reason its winrate is so low is because it's a difficult deck to play, pair that with the fact that the majority of wild players are absolute shitters and you've got the reason why its winrate is lower than it should be.
So no, no need to unnerf Raza "just cause" unless we unnerf everything else too.
I wouldn't be against it, if only for it to re-introduce another deck type for priest. Priest is toxic as hell in wild with big priest, and the other variants cheese you out with combos anyway (mind blast, nomi spam, divine inner fire OTK). Raza priest is less consistent than these and does pretty much the same thing. So to hell with it, the class is already beyond repair, at least give it something fun to pilot again.