Have used the new IDE for a while and see it as better than the old one. Here some feedback and a bug.
The new IDE, it does not seem possible to build&run without a device selected in the lower left “Development device logs” window. Is there a way to do this - I seem to remember you could do that in the old IDE. I am on Macbook Safari Version 10.0.1 (12602.2.14.0.7).
On Macbook 2016 12" the limit have been reached for how small the primary windows can be and still be practical at all.
In the model view the icons to the right (go to code, factory, settings etc.) disappear most of the time. The workaround for me is to scroll slightly, while the mouse pointer hover over where the icons should have been, and this brings them back.
When pulling up the top border to the log window (and development device log), to show more of the log, and then selecting another device, the log window resizes to default automatically. I would like it not to return to default size, as going through the log of 10 devices means you have to enlarge the log window again each time.
Device names in the device log window are line-wrapped and cut off in a fixed manner, even though there is loads of space for it. Means you have to press the gear wheel each time you need to see the rest.
Finally, with the old IDE, in and emergency I could log in with iphone 6+ and get by with checking a device log, even change a false to a true, build&run. I know it’s a tall order but I really miss that 
All in all Great work!