The arguments for follower boards are:
1) You get a double wall on the outside edges which cuts down on condensation and keeps them warmer.
2) You can remove a follower more easily than a comb covered in bees (the follower is smoother and seldom has bees on both sides of it.
The concept is to have a 3/8" gap on each side of the follower (a beespace) so that it is easily removed without rolling bees.
As far as the "square" concept, I think square is nice, but since it's not standard and a square Langstroth would be bigger than the cluster, the eight frame works fine. The easy way for bees to move is with the gaps between the frames. The difficult way in winter is from "frame to frame". You've eliminated some of the "frame to frame" movement in the eight frame box.