I mean, really, really, long. It's nice that the lower levels are so short, but once your buildings hit level 13+, upgrade times - even with a Main Building at 20 - can take anywhere around 8 to 10 hours depending on the building.
This is a serious nerf to people simming, and forces people to put resources into troops of course, but people who do not use gold are put at a massive disadvantage here since gold users and abusers don't have to wait 5 days of non-stop upgrading to get their Main Building to level 20, amongst other things.<br><br>Not only has the time for building upgrades been significantly lengthened, but so too has the cost of upgrading the buildings.
I'd like to propose these changes to the Main Building:
1. The Main Building should not be able to be immediately completed using Gold, like Residence and Palace.
2. The Main Building bonus at level 20 is 50% faster upgrades. Considering the increase in cost and time, this is not really worth it since you can upgrade a number of buildings in the time it takes to fully upgrade the Main Building. With this in mind, let's put more reason into upgrading the Main Building earlier by slightly buffing the upgrade boost.
Example: Level 20 main building, 50% upgrade time reduction, a Stable takes 11 hours to reach level 20 from 19. At 100% it would normally be 22 hours.
If the Main Building's time reduction bonus was at 40%, this would come down to a respectable, and altogether more fair, 8 hours 48 minutes. This would put it more in line with upgrade times of T4.4 and earlier, and it will feel even more beneficial to actually use your time raising the Main Building if you don't plan on using Gold to complete other structures immediately, or don't have Gold to use.
What are your thoughts on this?