Now remember who Wario was up against in Wario's Woods...
Kind of neat that the makers of the Mario baseball series remembered that, isn't it? Okay, they lost a bit of it by removing the bad chemistry between Wario and Toad in the sequel, but hey, that could be for game balance reasons.
I do remember the Toad one, but I completely forgot about him having bad chemistry with Birdo in Super Sluggers,cool stuff, but given that superstar baseball was already a gold mine of Wario content it's no shock that Wario's Woods would get a little love as well.
As for Wario's and Toad's chemistry changing (from an in-universe perspective anyway, out of universe it's probably really just for balancing purposes) :
I always liked to think that Wario was being a good samaritan by dropping his grudge against Toad, it's not like they had a big fight like in Woods ever again and heck, the little dude gave him a friggin' star constelation for his birthday:
So it's safe to assume that Wario abandoned the hard feelings against him at one point, althought I do wonder what chemistry they would share nowadays with Toad beeing a treasure hunter now...
