I stand more so by the slash lines that I posted than the scouting scale.
His hit tool is his highest tool, but he has enough power that he won't be an empty singles hitter with a high average.
There are two big questions for the value of Taveras (3 if you want to consider health, but that's every prospect) if you ask me.
1. How much power will he actually develop. This year was a decent sign. If he can be a perennial 30 homer guy, you have a complete stud. If he is a 10-15 perennial home run hitter, than you have someone with a lot less value overall. But if he can compliment that with enough doubles power to the point where he can still produce a +.500 slugging, then he is a perennial all-star. Anything less than that and I think his overall bat is going to be a lot weaker because his walk rate will never impress enough to carry him to that all-star caliber alone.
2. How long can he play centerfield and at what rate. He probably won't get to play center much in the big leagues in St. Louis. The front office seems to really like Jon Jay, no reason not to of course. Beltran is gone after this season, and Taveras while being a decent route runner and having a plus arm just doesn't seem to really profile as a centerfielder. He hustles, which you love to see, but he isn't gifted with a lot of natural speed, so he has to make good routes, and continue to hustle to be an average center fielder. His arm is nice in center, and certainly passable (even good) for a right fielder.
With the expectation being that he adds bulk to complete his bat and give him enough power to be a perennial all-star, I can't see him sticking in Centerfield. He'll get bigger, and likely a little less speed with it (he isn't built like a Matt Kemp for instance where he can hit 40/40).
I like Taveras, and obviously as a Cards fan I'm even more enamored. I think he is a .330 potential big leaguer. He has elite contact, all of his bats are covered in ball marks in the sweet spots only. He just doesn't miss very often, and he usually makes very square contact. His size will help establish his power. And if his power comes along, that will increase his walk rate.
All I want at this point from Taveras, is to see him develop the power. He can forget about playing centerfield in my mind (obviously you keep him there as long as you can in the minors and teach him that position in case you end up needing him there, or he proves he can play there and push someone else off, but Jay has like no value unless he is a centerfielder). If he can develop that .550+ slugging, holy cow.....I'm in love.
But we are a few years away from something like that happening most likely (no Trout most likely).
Anyway, sorry from rambling. Just a top rated Cards prospect, easy to chat about him.