I see what you are saying, and it does make sense, but Powersurge does have a point with characters like Storm and Magneto.
I think what you are driving at more, is the massive, brick like characters, like Thing or Hulk, should be more reflective of their ability to take damage, compared to the Cap Americas, Cyclops, and Storms. Well, maybe we should add that into Health too, Height and Weight. After-all, Endurance is not a reflection of the Mass and stature of a character, look at Storm. She has an AM (50) Endurance, but is not built like a tank. Instead she is muscular but lean and light.
Maybe we tweak your formula as such:
Strength + Weight divided by 2 (round up) + Height (in Inches) + Endurance = Health
this would give characters that are made of other Matrials beyond flesh a say in their toughness, and balance out some of the other oddities like Storm's and Magneto's high endurance rank. Here is 3 examples using the Thing, Storm, and Cyclops:
Thing
6' tall, 500 lbs, UN(100) strength, MN(75) endurance
72 + 250 + 100 + 75 = 497
Storm
5'11", 127 lbs, TY (6) strength, AM(50) endurance
71 + 64 + 6 + 50 = 191
Cyclops
6'3", 195 lbs, TY (6) strength, RM(30) endurance
74 + 98 + 6 + 30 = 208
Is this more in line what you are thinking? This gives a bit more emphasis to the size and stature of a character too. So, large hulking characters like The Thing and Juggernaut will be more "durable" than more human type characters.