I think you should only be limited to 50% of your growth at the most. I mean really come on to get 100mil-120mil CER it would cost a fortune, then you will be comparable to the other players that haven't reached the 2bil cap yet. Planet production is getting a triple hit at the moment with fleet costs jumping and charisma costs starting to grow rapidly after 500. 50% limitation is perfectly reasonable. You should reach around 60% limitation at 5bil planets.
Also something nice i just noticed (and yes i like this) the cost of production really increases after 1000. This will help slow the growth rate of top players in ascended and may eventually make growth comparable to main (which i think is very important).

Also the conversion rate for APP just sucks again lol, it should be around 10 times higher then it is currently for ascending, and will need increasing again until the growth between the servers settle.