For the most part I like the balance changes in GE1-4, the amount of FPs, Goods and Units have increased, and the new selection kits give roughly the same number of buildings, but with increased flexibility of selection kits. **However**, there are two big exceptions.
1) Number of diamonds have been more or less cut in half, from around 161 to 81 diamonds per week on average. It also doesn't help that in practice GE5 will require diamonds for extra turns. 2) The time it takes to get a FoY has been increased from 4.35 weeks to 16(!) weeks on average, and the time it takes to get FoY shrink has been increased from 2 to 16(!) weeks on average. That's a x3.68 and x8 increase, respectively.
It's clear why, they want to limit free diamonds, but as a player I strongly dislike this. It's one of the main remaining ways of getting free diamonds, at a time where diamonds are worth increasingly less as more cash-only features are added. I think a great way to incentivise players to play GE5 would be to add additional diamonds to the rewards, for example a big diamond reward at the final encounter. I think that's something more players would be willing to work towards.