Hitting doesn't really factor into Gold Glove. If we were Tampa Bay fans and watched all the Tampa Bay games we'd be saying the same thing about Kiermaier. Can't go wrong with either really, as they are both stellar on defense. Pillar maybe less naturally gifted compared to Kiermaier for CF defense, but bigger heart nonetheless. I don't know how their defense numbers are this year, but in previous seasons, Kiermaier had the slightest of edges.
I will say, I was really impressed watching Jarrod Dyson in the four game series - he's so fast and gets such a good read and jump that he doesn't need to make highlight reel catches. Small sample size though.
I'd like to see them go back to picking three outfielders for Gold Glove (it was once like that), instead of LF, CF, and RF like it currently is.