It's very frustrating and not very fun. As soon as the Mage Tower is active the best way to get AP is by spamming Random Heroics in a premade group. This method gives you upwards of 6-8 million per hour (~ 2 or 3x better than farming M+).
Mage Token is ~50% drop rate for 520k AP (AK 27) from every single boss in Heroic with no diminishing returns (i.e. repeatable endlessly and doesn't require a key). Whereas the Mage Token can only drop from the chest containing AP on M+ (1 possible drop).
A solution would be to not give a static value to the token. Instead, make the Mage Token duplicate whatever token dropped from a boss. This would make M+ viable again for farming and completely eliminate the Heroic farm spamming (Heroic boss tokens are only 70k @AK27).