There's nothing to suggest that Gattis was improving as a hitter other than a few more balls eluding defenders. He still hacked at everything and didn't draw walks (something that Davis actually does, which is why despite batting in the .230s this year has led to Davis having a better OBP than Gattis has ever had.) They were the same age. Gattis was 27 last year, Davis is this year. Both have a bunch of years of team control left. It's a completely valid comparison and I would actually probably prefer Davis to Gattis. Now I think the Astros overpaid for Gattis at the time and I obviously think that now with Gattis being horrible this season but all it takes is one team to overpay and we could get a really nice haul for Davis.