If you like playing him and using him frequently, go for it. Most people will tell you to wait. If he's not someone you'll use and are just doing it for TB, don't do it.
If you need an r3 for Thronebreaker, then definitely yes.If you already are a TB, then I would suggest you to hold and use your skill t5cc on a top tier skill champ like Aegon, NF or at least a champ at Falcon, MoleMan, HitMonkey etc. range.Having said that, I have my 5* Masacre at 5/65 and have used a spare skill AG on him also.He is very fun to play, does good damage and can be useful in some lanes or fights, but 5/65 a champ is definitely very different from r3 him.Hope that helps 🙂