What Warcraft 4 realy need to succeed ?

Warcraft 4 is huge risk. Mobas are popular. Strategy games not so much. 
Maybe it has more chance with best campaign world has ever seen. So people mass buy it. We all know that Warcraft has huge fanbase.

But I have feeling that they don't even need to make Warcraft 4 if they want competetive eSport game. 
Just upgrading TFT or making new expansion would be so much popular!

 

Please Help !
Thanks !

I didn't find the right solution from the internet.

References:
-https://us.battle.net/forums/en/bnet/topic/20759327173
-Mobile Video Launch