Ignoring resistant color
I agree.
Resistant color is roughly equivalent to 2x actual HP ( a 3x neutral color stack attacking versus a 3x strong color stack attacking ), but a bad center is still a bad center ( looking at you purple 3* Prisca ).
So a X*+1 resistant color center, that is also a bad center hero, is worse than a X*+20 hero, that is a good center, of the other three colors ( looking at you Bauchan the Guinevere of 3* tournaments ).
X*+20
People are learning the method for tournament matchmaking.
5x X*+20 heroes with maximum costumes and maximum troops are best for tournaments ( see notes ).
If you have a rainbow X*+20 defense team with maximum costumes and maximum troops it will often do better than a 3x X*+1 resistant color defense team.
Few people have 3x X*+20 heroes for each color.
Tournaments with 1* / 2* heroes would have required the least emblems, least food, least iron and least RNG to run a 3x to 5x resistant color X*+20 defense team with maximum costumes and maximum troops.
Notes
([Primer] Tournament defense points or Why was my defense team attacked ZERO/ 3000 times)