I've some feedback from new installer partitioner, and I'm a old user that uses a lot the old model. Normally I use the "Custom Partitioning (fox experts)" option and everything here is about it.
In new partitioner, I see a list of my discs and partitions in a area "Available Storage" , and I click in one, selecting, and don't see nothing to edit, or some action to do. After a few time I go to side nav menu "System View" click in hard discs , my /dev/sda . These goes to Overview . Now I go to Partitions and find my "old screen" with Add.. Edit.. Resize and Delete... Also , after I discover that a double click in a partition or disc in the first screen goes also to partitions "old screen".
To me it was easy when a see the list, select one and just choose "edit" or the action that I want.
By the way the new partitioner gives me a real nice vision when I have nfs, LVM and another things like crypt and RAID. Also the "Settings" option, like "of mount by"" and "visible information" is useful.
My suggestion is that you can keep the actions in bottom of the list to direct edit the things.