In Honka's defense, not many real games so far. USA, Canada and the potential QF game will tell way more.
I'll take your word for it as a person who watches Dallas more closely than me but I want to explain my thought process on the subject.
I haven't watched that closely of your defenders' situation but the fact that Honka played only 50% of the games and the issue wasn't injuries AFAIK makes me thinking that they see Honka as a very much expendable piece or could it be that it gets better for Honka now that there's a new coach after Lindy Ruff era?
Klingberg taking majority of the PP time and I'm guessing Heiskanen will become the second most important PP defenseman for you. Then I'm guessing your next option is Honka, while Lindell isn't bad at that job either. My knowledge about the situaton kind of ends there and I don't know if you got more offensive, possibly smallish defensemen but I assume you have 1-2 more of them, so I think it doesn't leave that much room for Honka. Like you mentioned him being a rightie is probably the biggest factor why Dallas might keep him for longer. Could Dallas already be thinking about extending him cheaper by limiting his minutes a bit and then increase the minutes, sort of like the case with Nutivaara of Columbus?