The EXP requirement isn't the part people have a problem with, it's the punishment for not meeting the minimum. You're wanting to give guilds benefits for being a certain level and you're knocking people down if they're already there but want to play the game their way (like a sand park game lets you do). What you're proposing is punishing guilds for choosing to do something else that day.
Currently:
Statement- You should be rewarding players and guilds for reaching a daily milestone.
Example- Day 23 of the Daily Tracker rewards players with 6 Gilda Stars for logging in and clicking a button.
Statement- If they don't reach that milestone, they simply shouldn't get the reward for that day.
Example- Day 23 of the Daily Tracker gives players nothing if they don't click the Login Tracker's button.
The problem:
Statement- Your system is taking away something the players of a guild built up if they choose to not reach a milestone.
Example- Day 23 of the Daily Tracker removes 84 Gilda Stars from your inventory if you don't click the Login Tracker's button.