I think Wild is a fantastic format and great fun. I also think it needs to be allowed to be the crazy, high-power level format that so many people seem to be against. Trying to perpetually balance Wild is a losing battle and would just end in neutering everything fun about an eternal format.
Having said that, what Blizzard could do is some sort of compromise - a 'Wild-ish' if you will - where some cards are banned. That way the people who want a lower power format are satisfied, and those who want to play with all the cards in the game can do so.
There's a ton of modes that Blizzard could add, but I sort of understand why they don't - every additional mode they add is another mode for people to get mad at them for not balancing exactly how they want, in addition to all the split playerbase concerns.