For me I always saw the drain lines as being easily broke because ours hang down a good 12-14" outside-free in the breeze. Luck is haven't yet. The lines themselves go up inside rear skirt cabinet to wing floor, 36" or better.
The dumb part, in my opinion, other than too long, is the outside length being full of water, subject to freezing- no way to address should they just break or burst.
I don't live nor camp where freezing would be concern. I don't use tools to loosen or tighten the drain caps and location actually would be hard to whack. So they work.
If I ever addressed I would shorten considerably. Adding valves inside the cabinet where line pass doable but unheated so unsure resolve much.If they broke while out would be inconvenient at worst, I can access water in tank or pump into a bucket from broke line.
Dumber in my opinion is no endpoint valves anywhere in our camper except water heater. If I were to add valves it would be at sinks and toilet, likely toilet 1st to throttle it.