As howtheduck noted, the Elly of original history simply avoided having fun with the children based on the lunatic theory that her brain would erode and she'd become a babbling infant were she to do so; now, she seems to be actively trying to prevent them from having any fun at all.

The part which is difficult to understand is why Lynn Johnston has made this change with new-run Elly. The idea has been that her readers would be able to look at Elly's experiences and see something of their own lives there. When the kids make a mess and Elly looks gobsmacked, Elly represents all the parents who had to clean up a mess their kids made, for example. But for things we have been seeing lately, "Elly doesn't want the kids to play, or John to play a gross videogame with Michael", Elly has moved from the everywoman to being like some matron of an Oliver Twist-like orphanage or Roald Dahl parenting figure. "Kids must not have fun. It is wrong."

We have seen recently Lynn Johnston's own personal beliefs about the young in the podcast where she talked about young people not having the same work ethic she had, i.e. show up on time, etc. I wonder if this new aspect of the "no fun" Elly is a reflection of Lynn's idea that young people today are not serious enough about what they do.