The idea is simple. This potion will allow you to **use all of your heroes when they are upgrading**. So you don't have to attack handicapped in clan wars or in the new Ranked Battles to come.

  
Why should this exist?

As there are 100s of levels and multiple heroes, you can't just be upgrading 1 or 2 at a time, so even if I buy the book of heroes every week, I still cannot do CWs and CWLs freely, which you know, is literally playing the game.

  
But won't players stop buying the Book of Heroes?

1. Yes, I suppose so. Hence we make this potion cost a lot of gems say from a 100 to 200 gems for 1 potion so it could be better to just but the book. 

2. Or get 1 potion in the raid shop for like 300 to 500 RM that way you'll only purchase like 1 (considering you could buy the lab potion and ores).

3. Or you get one at the end of the season track 1 for f2p and 2 to 3 for p2p.

4. You could get 3 to 5 of them in the Clan Games.

4. And you could get them in chests and buy them in the in-game and Supercell store.

  
Scenario Analysis;

1. F2p - You can get this every weekend with RM, you are not going to buy them for gems or money so that's out of the equation.

You will get 1 or 2 per month in the silver track and 3 to 5 in the Clan Games for the next month's CWL.

So at least you can do anywhere from 30 to 60 % of your CWs and CWLs with heroes even under them upgrading (depend9ing on how active your clan is).

  
2. P2p - You can get the same as the F2p but also from the shop, from the trader gem shop etc and the Gold Pass, so you don't have to worry about not having your heroes when doing CWLs or CWs or just in general.

  
Now I want to say - the specific numbers and how and how much of these you earn is debatable. But it is important for a system like this to further enhance the gaming experience. Even as a pay to win, you still cannot stress free upgrade your heroes and it's been 10+ years the game has existed and it's way past time something like this should have existed but it's never too late to add it.

Update to Idea - Coffee Potion