Yelich has a 766 OPS versus LH starters, so he should still start. However, he gets destroyed by LH relief specialist, so they should PH for him consistently.
Yes, the team doesn't have enough quality, complete players. Adding 1 high quality hitter to this team would change the lineup significantly, especially when he takes McCutchen's roster spot so the team has some positional versatility.
Having 2 RHH CFs on the roster, one they can't hit and the other that hasn't hit, is also a detriment.