I have been experiencing similar too, as have another couple of users in our organisation. Frequently, the dropdrown menus tend to reset and/or you have to log in again if no selection actions are taken immediately.
In the end, if you can just get a REST URL, any REST URL, preferably with a search filter and number of row one too, then you have the core to build the rest of your REST URLs from. I use the REST documentation and construct my own REST URLs with a list of profiles and reports from the "list profiles" (if you can get to that one in the first place!).
Nevertheless, it would be good if the Generator response was quicker.
Any update on this?
It is killing me. I am working on three different dashboards at the moment and the generator is highly unstable.
Also is there a limitation to how much you can extract now?
I used to be able to extract +3000 element, but it is so slow now that IE and Excel crashes.
(tested on two different computers on different connections)
I really hope to see it back on track soon, as we have gotten a lot of positive feedback on the dashboards we have created, but now they often crash when the user press update.