Some areas are excellent for cycle times and scooper lakes...Ontario, MB, SK come to mind. Parts of the Okanogan as well.
Alberta and northern BC...not so much. Some lakes especially in the NE AB but frankly I don't get to see the CL-215's or AT-802U's much due to lack of scooper capable lakes. There's some big water bodies by surface area but many are more like shallow duck ponds than true deep lakes which can cause issues.
I know Ontario has the Twin Otter scooper units but have never seen them in action to compare against the AT-802U. CL-415 vs. CL-215 need a medium sized lake and while I know they can land on rivers (saw one land in Thailand in middle of a river in Bangkok) it's a question of straightness, depth, and banks to allow safe approach.
The other challage is the size of plane vs. topography....I love the sights but hate the experience of flying over the mountain ridges and dealing the the air thermal changes on each side. Larger aircraft tend to handle it better than the smaller tankers like the AT-802's but if conditions are good the little guys can nip into the valley where the big units like the Electra L-180's can not.
Point I'm trying to make is I don't know if there is a perfect airframe for use across Canada. There are some very good planes for X situation and there are better planes for Y. The market seems to be stabilizing around three models though....CL-415 (and the future CL-515), Bombardier Dash 8-Q400, and Air Tractor 802's
Two of the 3 designs are Canadian and built here so that's a pretty good track record. Especially when you see them in use in other countries around the world.