Maybe stay where you are, untill there is something you really really really want?

Thats where i currently am.

I have never been a fan of 2 arrangers on top of eachother, as they will both offer the same things.

If you would choose the SD40, i would add a Jupiter 80 as the Roland soundsource.
If you choose the Genos, add an Integra 7 as the Roland soundsource.

Happy with the G70, just add more VST's, they will allways work no matter what keyboard you play.
If you want more keys for those VSTs's add the Native instruments komplete kontrol mk2.
Or add a nord stage 3 compact on top of the G70.

So many ways one could go, but having 2 arrangers would not be my choice.
Unless you are not happy with the style quallity of the G70 and only want to use it for Roland sounds.
Which seems not the case.