I doubt there are enough cities in Atlantic Canada to justify a fourth CHL league, nor is there likely any interest by the CHL in such a project (although it would solve the messy situation of always having to invite the host team to the CHL championship tournament).
Doing so would destabilize the QMJHL, which suffers from the fact that Quebec has a relative lack of medium sized cities interested in supporting major junior hockey, and greater Montreal is fixated on the Habs to the detriment of any lesser teams. The QMJHL would be much better off if, for example, there were three teams from the greater Montreal area. Removing the Maritime teams from the Q would leave them with just 12 teams, some in shakey small town markets.
I would think the minimum size for a new Atlantic Major Junior Hockey League would be 12 teams. We currently have six, therefore we need six more.
- Fredericton is a no brainer, but there is no satisfactory arena and the city is currently fixated on university hockey.
- St. John's is pretty much mandatory too, although travel cost to and from the Rock are a huge issue. The recent introduction of a PAL service to Moncton from St. John's would be a help.
Beyond this, the pickings get slimmer. I don't think there is anywhere else in NL that would be viable. In NB, Edmundston is most likely, and is a proven hockey market. Truro is the most likely market in NS to join the league, and they have a new arena which might do if a little seating expansion were possible. This gives 10 teams.
Finding two more teams would be really tough. Kentville possibly for NS and Summerside maybe for PEI. Kentville does not have an appropriate arena, and, while Summerside does, it is a small city with only about 15,000 people, and would rival Bathurst as the smallest market in the CHL.
Also, if the Maritimes went whole hog on the QMJHL, this would be the death knell for the Maritime Junior Hockey League. I can't imagine how they would both survive.