Definitely get the comparison, they both have that slightly unpredictable edge that can be spectacular or end down an alley.
Obviously Tavares is much younger and should have the capacity to improve. I actually think that Pepe is much more refined now than when he first joined as well. He works a lot harder out of possession and seems to give the ball away less.
I think Tavares is fortunate playing in this era. I don't think there's been a time in football where defensive ability matters less for a FB / WB. With his attacking inclinations and his athletic ability he's 3/4's of the way there already.
We've only really seen him up against pretty poor opposition though. For me he's got a long way to go if he wants to usurp KT, who admittedly hadn't been at his best recently but still has a hell of a lot of credit in the bank.
I prefer to see Tavares as a long term project and an understudy to KT as it stands.