To me, Lassgård is the "right" Wallander. Haven't seen the BBC version, so I won't say anything too specific about that, but I agree as a book-verse fan: Wallander/Martinsson doesn't compute. Wallander put much too much value on integrity to ever seriously consider Martinsson as a partner. Wallander needs someone who he can look up to, not another person seeking guidance or easy solutions. Mutual respect is the clue and cornerstone of all Wallander's deep relationships and his respect for book-Martinsson is declining throughout the books (in my view).

(Oh, how wonderful to get to geek about the Swedish version Wallander! Hiddleston who? (and other f-listers would wash their hands of me if they read this).)