An 8 team top division would not make sense, because it would damage the popularity of the sport in countries like Germany, Slovakia and Switzerland, which would be playing in the 2nd tier constantly.
A 10 team tournament would make more sense, but in that case a single-group round robin would not be possible, which sort of destroys the emtire purpose.
Holding it every two years would also make sense, but it would only work with some kind of an agreement in place between NHL and IIHF, which is not going to happen.
There's a reason why we're stuck with the current format. Reducing it to 12 teams could work, but the net benefits would be pretty negligible. If Russia and Belarus ever become civilized countries again, we would not really have any 3rd tier nations in the top division anyway.