I'm siding with Pokemon's decision that ice is not very effective against fire. Not going to create a fire to test it but since fire can melt ice it seems correct.
You're absolutely right, it would have make sense for Ice Man be weak to Fire Man's attack, and Fire Man to be weak against something else. Alas for you, that's now that the creators of Mega Man decided.
Discovery of the optimal sequence was part of the thrill of the game. It was a clever mechanism for replay value.
Absolutely, and it still is.
What is also interesting is that there is not one optimal order, but several. Take MM1 for example, you could start with either Guts Man, or Bomb Man, that would be the "normal" way to beat the game. You could also start with Cut Man or Fire Man if you want a good change and something a bit harder. But starting with Elec Man or Ice Man would be a really, really though challenge!
something like Elec Man in MM1 is completely trivial if you have Cut Man's weapon, and friggin' impossible otherwise
Agreed, I even tried with a save state before the fight to defeat it without any help, and even then I had to give up.
Also the OP mentions:
Mega Man 7 has the bosses coming in two rounds of 4 bosses, so the possible orders are more limited. Mega Man & Bass is similar on that it allows a limited number of bosses to be available to challenge at a time, and should be defeated to alow more stages to come.