Gems of War 4.0 will have the following features:
3 new maps for a total of 4 continents.
Each continent will have enough room for 50 kingdoms.
Each Kingdom will have a new troop type: The General.
New Troop type: Demigod
10 different mana colors.
New Gold mines to harvest.
New Soul mines to harvest.
New Traitstone mines to harvest.
All armies will now be led by a general.
All battles will now be 5 x 5.
New Events: Gold Mine, Soul Mine, Traitstone Mine, General Event, Holiday themed event, New Troop Events, Class Events, Metal Events, and an Endless event.
New Guild Events: Guild v Guild for a week, Guild v a Kingdom, Guild Holiday Themed Events.
Anything else you feel will be in GoW v 4.0?