I got a response from a Linksys engineer and this is what I took away from the discussion.
- The WRT1900AC with the Linksys firmware is designed as an extremely powerful home based router.
- WRT1900AC OpenWRT support is for more advance features not found in the Linksys Firmware for home networks.
I agree with this concept since I did much the same process with the other WRT models. When I needed more advanced features with the previous WRT models I would load firmware like DD-WRT and others.