Can Astros outfielder Jake Marisnick improve with the bat?

From the Minor League Ball mailbag:

"The speed and the glove are nice but will Jake Marisnick ever be a good hitter? I know he has some power but his on-base percentage is a real stink on the offense. That's not a typo! I watch a lot of Astros games and he just isn't very good"----A.J., Round Rock, Texas

Unlike A.J., I don't always watch Astros games, but when I do, Jake Marisnick usually doesn't hit well. But you're right, A.J., Marisnick does a lot of other things: steal bases, flash the leather, hit for occasional power. Despite his overall weak hitting (his wRC+ is just 80 this year), his other attributes have given him a positive value with a fWAR of 1.5 in 320 plate appearances. That's nothing special but it can keep him employed as a fourth outfielder type for awhile.

He's 24 so he still has time to improve. But will he?

We can't say for certain of course but there are some signs of progress in the trendlines. There's not much progress in walk or strikeout ratios, but we are seeing an increase in isolated power which has moved from .064 to .077 to .158 over the last three seasons. His wRC+ and OPS+ numbers have tracked that power increase, going from 29 to 66 to 80 and 30 to 72 to 82.

More confidence would be justified if we could see some improvements in his approach but at least there is more power now.

Using the patented WAG method, my guess is that Marisnick will do this slow improvement thing for another year or two, then have a couple of much better seasons in the age 27-28 window and perform well enough to be a decent regular. When his athleticism starts to fade around age 29 he'll fall apart pretty quickly as a regular, but his glove will keep him in the picture as a backup for a few more years, assuming he's not too expensive.

What do you guys think?