I agree with lots of people that we should be able to trade resources.
With that in mind i made a plan that everyone wins (P2W/F2P/Playa)

We should use Metals 'n Stones to create Crystals
When we think about crystals matter came from rocks (as gems) that's why using Lab to work with - and management at fortress page (will be explained) -

So when we reach level 20 this new feature is released.

That being said
what to do with 16~19 levels?
- Increase the production!
(Woodcutters/Quarry/Souls/Gold/~maybe even XP) - continue with 5% per level total 20% or 25% (if lvl20 also upgrade)



To make that work
a gratuate selection like City Guard that scale the time and resources

That time can be instantly by using mushrooms but way more expensive than gems are (since gems requires luck)
Also, time will be running above the Labs construction with some animations like the ones that exist

sorry about paint photo


- Ideas to scale