I think it is pretty common to place the water tank drain near the water tank. My ACE 27.1 does this, and my 1991 Holiday Rambler did this. This design element allows for complete emptying of the tank reducing frictional losses. It's not a design flaw just something you don't like. You could easily add a sprinkler electrical valve in line and just push a button. Whder if there are any 12v activators. Heck do it to all of them. Then wire them all together and just push a button. I like that since we camp all months of the year and do drain during the winter months.
__________________
|