I think the tinkering with the stance last night was entirely related to Manaea. He looked like he didn't see his pitches well at all.
I'm not worried about Votto. Earlier in the year he was hitting the ball solidly, but had some hits taken away by the shift. Half his ABs have been against LHP too, which isn't going to be the case the rest of the year.
They've faced the Braves, Dodgers, Padres and Indians to start the season. Doesn't get much tougher than that.
Wouldn't be surprised if things start to turn around offensively for a lot of guys when they get home Friday. Temps will start warming up and the competition isn't quite as tough. If things are still where they are after they play the Brewers and Pirates 14 games over the first part of May, then I would start to get concerned.