the prarie provinses should be worth 1 maybe 2ipcs
ontario should be worth 3ipcs
bc should be worth 1 or 2ipcs
martime provinces should be worth 1.5ipcs
quebec should be worth 2.5 ipcs
Being a Canadian who knows a little something of our history, I would like to say no. Were we important? Hell yes, pilots spies, special forces and not to mention our soldiers and the navy we used to put the hurt on Germany with did loads. But as for material value, we were much lower. Yes we have lots of resources, but they were not as important as some may think. Food and supplies came from here because UK needed them, and too be honest our IPCs are mostly represented in those of the UK, as they were unable to supply most of what they needed for the war, so we shipped it over then they put it to use. THe few IPCs in Canada represent naval and army and air units we raised ourselves, which was quite impressive at over a million fighting men, was next to nothing when compared to other big powers. So my advice, my young friend, is build a minor IC in the maritimes and build detroyers out of it, and just think that there are loads of Canadians fighting, they are just in with the UK armies.
Also, to validate my point go visit Fredericton NB, my last home before i moved to quebec and see how much it has grown in 40 years, as durring the WW2 period, very little of it existed, a few blocks aroiund city hall and some farms, it was almost all woods. This was common of Canada in the period, and durring WW2 we only had 11 million people, and only due to immigration from other nations have we reached our current population, which is still less than 10% of the US.
As for any other country like holland, etc being powers, no, as they will just stretch resources as has been mentioned, and in reality gave little to the war in most cases or just became part of the larger war effort of their big neighbours. If you want to play small countries in WW2 get Hearts of Iron for the PC, and see how fun it is to be one of those nations next to germany.