After thinking about it for a day, here are some of my thoughts:
1) WB's portrayal didn't change per-se. We've already seen that he's hesitant to go on a "revenge tour", when he didn't personally go after BB and was also hesitant to let Ace go at first. He started a war with the marines, because this was more like a "rescue mission" instead of a "revenge tour" and there was actually something to gain for him personally (getting Ace back). In Oden's case, WB knew that he was dead and that a war with Kaido would cause a lot of casualties for him/his crew.
2) That brings us to the main problem, which didn't change with this chapter: The whole Oden-WB storyline is kind of cringeworthy and not really thought through. WB and Oden were as close as it gets. Heck, Oden even founded his own family (wife, children etc.) on WB's ship. We saw that WB loved Oden, even calling him "brother". Even when Oden temporarily left with Roger, they made sure to see each other again asap. Yet somehow WB never bothered visiting or helping Oden, when the latter returned to Wano. Oden basically had to dance like a fool for five long years, without his sworn brother ever looking after him. That's just bullshit, sorry. WB had to know that Kaido was on Wano and Oden was in danger, everyone in the New World knew it ffs, so don't come with "bUt NeWs DoN't CoMe OuT oF wAnO!!"
So my conclusion: His portrayal didn't change, but him not looking for Oden, after the latter returned from his voyage with Roger, still doesn't make any sense. Especially considering that WB must've known Kaido was on Wano and still didn't even visit for over five years ...