In the very same post you are implying that it is okay to project Bethancourt as a decent to good hitter by using Yadier Molina as a potential comp, while dismissing Gattis as a one tool player using a small sample size. Isn't it possible that Gattis could improve his plate discipline and become a more complete hitter? I'd argue that there's every bit as much chance of that happening as there was of Molina going from a sub .700 OPS guy to an .850 - .900 middle of the order hitter. I know Gattis is a good bit older than Molina was when he was putting up average to below average offensive seasons, but Evan also has a lot fewer miles on him behind the plate. At the time of his breakout season Molina had 1,081 games (major and minor) at C, while to this point Gattis has 166.
Gattis probably won't develop any further physically, but he's still very limited in baseball experience. He has ample opportunity ahead of him to improve the weaker parts of his game.
I'm much more worried about the prospect that Evan will flake out and head for the mountains again if he hits a stretch where things don't go well for a while than I am of him failing to continue to develop his skills over the next few years.