Basically what if the training time for troops lowers every time you upgrade it. Like a wizard takes 8 minutes to upgrade but a level 3 wizard would take 7 minutes and 20 seconds because 20 seconds is deducted every time you upgrade the wizard.
Second option is making the barracks 2x faster permantly.
100 gems for the first barrack boosted
500 gems for the second barrack boosted and so on
This are my ideas on how to lower training time.

