I've seen him too, and I second what Patti says about him filling out. I don't think he's actually 5'10" (5'8" is more like it), but he's pretty strong. His swing is less inside-out now and he's driving some balls to the gaps. I thought he was the most impressive of the 3 OFs when I last saw Potomac this season (prior to Soto's pit stop there).
Also, I don't know who thinks his arm is "fringe-average." From what I've seen, it's above average and more than enough for CF. For example, I've seen him uncork throws from medium-deep left that are accurate and come in on the fly to home plate with some zip on them.