@FIRERoad - You compared an S&P 500 index fund to Wellington Balanced Fund, which makes me wonder if you know the contents of the balanced fund. It holds about 1/3rd bonds and 2/3rds stocks. A better comparison would be to VTI (total US stock market ETF) and BND (total US bond market ETF), in the same proportions.
VTI has an 0.04% expense ratio, and BND an annual expense of 0.05%. So in the same mixture, you could achieve a 0.043% expense ratio invested passively, instead of actively.
This also highlights another problem: unless you're near retirement, 1/3rd bonds is excessive. You want mostly equities, not as much in bonds. You can see this in target date funds, which hold only about 1/10th in bonds for those far from retirement.
I'd suggest you shift to the S&P 500 index for two reasons. One being you can save on expense ratio, even if 0.06% is the only option in your retirement plan. And second, it will get rid of the 1/3rd bond allocation you hold right now. If balanced funds were the only way you can stomach the market, then they might have a place in your portfolio.