That's why I knit socks on 4dpn with a 5th working needle... There is much less tension at the point between the needles, so no ladders... Much more comfortable to hold and work, too.
That's purely my opinion and experience, but I'm sticking to it!
You are right about this for yourself. I too am a dpn sock knitter and find that knitting with a 5th needle is so great especially when picking up the stitches along the heel flap. :thumbup: