I believe there can be a balance. No need to get rid of all the mascots but we do need to focus on some new ones. Pikmin were Nintendo's last big mascots. However, now with things the way they are developers (mostly nintendo) are afraid to deviate from the formula for fear of failure and financial loss. What would you rather buy with you money? A Mario title? or a New hook featuring a new world and character? Most likely Mario. People are also afraid to try untested things for fear of quality and longevity of the title.
Whatever happens we need to find something new. I myself have been waiting for a new set of characters to fall in love with, alas...nothing yet.