You can. Make the Mariucci Classic similar to the Great Lakes Invitational and pit Minnesota against 3 of the 4 in-state rivals on a rotational basis. Then pit the one left out of the tourney to a 2 game NC series. Keep an eastern rival series, but add UND instead of the Big Ten Showcase, and leave the last series for whomever we feel the need to play (WCHA or not).
Then, in addition to the 5 current Big Ten teams, keep in mind 1/2 the schools being talked about for expansion have hockey teams, so that's 6. Penn St has openly admitted they want to be D-I and want to skip the D-III ranks to get there. They certainly won't make money playing Quinnipiac, RPI, and Niagara -- but should there be a Big Ten conference -- they certainly could sell tickets to play Minnesota, Michigan, etc. With 7, Illinois would be an easy choice to also make the jump with Penn St -- and there you have it: 8 Big Ten teams.
To remain in the WCHA is negative for our program. The top recruits can go anywhere in the country, but they used to want to go to Minnesota first. Now with 5 teams in state, UND, UW, etc all so close and respectable -- it's hard to keep that. We will fall to mediocrity in the near future (it's already happening). To go to the Big Ten would surely make kids think twice about playing at St Clown or Mankato... who wants to play tiny schools when they can be playing prestigious one's weekly?