Right now, Anthony Rendon has a 101 OPS+. Since he and Taylor are on the same team, you can maybe look to Rendon OPS as what we would want from Taylor to be a good every day player with his defense. Rendon's slash line is .270 / .348 / .410. Yangervis Solarte is another 101 OPS+ and Ben Zobrist is a 99. Their slash lines are .278 / .344 / .407, with SD as a home park, and .233 / .347 / .395 in Wrigley. OPS+ doesn't look at average. A walk or an HBP is as good as a hit in OBP, but power is needed to make up for a low average in SLG.
Taylor right now has a respectable OBP (.333), driven by a high average for him (.275) and a high BABIP (.407). What he's not yet doing is hitting for power. His career isolated power (SLG - batting average) is .132. If his slash line were .275 / .333 / .407, he'd be doing very close to what Solarte is doing. Add in the defense, and he's a good CF. however, he needs to reduce his K% from nearly 1 out of every 3 at bats so that when his BABIP comes back to normal levels around .320, he's putting enough balls in play that his average does not suffer. He needs to do that while boosting his power (doubles, homers).
All of this is just playing around with small numbers, but the rate stats gives you a sense of what you want MAT to do.