I really don't mind B1G hockey only having six teams. It helps to build a rivalry by playing each other more. Until last year, Ohio State had only played Wisconsin and Minnesota in hockey a handful of times throughout the previous decades. Now we get four games against each team, plus any additional games in the conference hockey tournament. If more teams are added, it is likely that OSU would play fewer games vs. Minnesota and Wisconsin, unless they took games away from the nonconference schedule and added additional games to the conference schedule to compensate. I would rather OSU play Wisconsin and Minnesota 8+ times per year than play fewer games with extra teams in the conference, especially if those extra teams were "affiliate members". Now if those teams were B1G teams adding the sport, then I would be ok with the expansion because its in-conference. However, as has already been pointed out, it is not likely to be added by anyone else anytime soon unless a big time donor steps up.
Since the B1G already receives an automatic bid to the tournament, the only reason to add more teams would be if the television money more than compensated for the additional team or teams.
What I would like to see would be for Michigan and Michigan State to add Women's Ice Hockey programs so that we have the minimum requirement of six teams to play women's ice hockey as a conference sport. Given that the infrastructure is already in place (same ice as the men skate on) and given that Title IX always leads to the need for women' s sports, it seems like it would be more likely for women's ice hockey to be added at Michigan and Michigan State than it would be for any other team in the conference to add men's ice hockey in the first place. With four members (Ohio State, Penn State, Wisconsin and Minnesota), women's ice hockey is now the sport with the most participants in the conference that is not currently a conference sport.