I was just about to post that, haha! I agree completely since me and my friend wants to do some lucky block challenges and maybe create our own modded survival with small mods. It should have a limit just like for plugins so people don't go overboard. Anyways, I love the idea a lot and please add this Aternos! You are the #1 server hosting after all and this will make a huge improvement! 
Posts by CoolerPlays
The Aternos forums are now deprecated
Learn more about this change here.
For help regarding Aternos, we recommend you to visit our support center.