I've tried, a few more times, to get used to GMS2, and the IDE is still not doing it for me. I think the root of the issue is that concepts like columns, tabs, and workspaces all place too much restriction on where code is located on the screen and how it is overlapped with other elements compared to windows, even when all the settings are set to the most permissive options possible, and, when used with a purely window-based workflow, GMS2 is relatively awkward compared to GMS1.
A couple of options could make GMS2 much more usable for users who prefer purely window-based workflows:
1) In GMS2, there's a setting that lets you open scripts or events in a new tab, which you can then drag free to make a window. The workflow would be accelerated-- and a relatively wrist-intensive task removed-- if there were an option that, when enabled, would automate the second part of this process, and open the code directly in a new window.
2) In GMS2, if you have several windows open, and you open a new window by the procedure described above, in the process, the base level of the IDE will be moved above the windows you have open. In order to restore one's stack of other windows to the screen (in my case, they'll have been stacked and sized and partially overlapped just so, in a way that probably just looks like a mess to others, but is exactly how I want it to be), one must go down to the taskbar and rescue each of the existing windows, in just the right order. The workflow would be improved if there were an option to open new windows (or tabs, or whatever else) without bringing the home window to the front.
Also-- and this is a much more minor thing-- although I work mainly in code, I've experimented a bit with the DnD mode in GMS2, mainly to see if it was at all friendly to the way I'd work in GMS1 (i.e. 99.9% code, but with the occasional DnD block, just to save on typing). Long story short, it wasn't. I think that things could be much improved for two kinds of users-- users who want the option to occasionally mix in a little DnD while working primarily in code, and users who started in DnD and don't like the usual route of switching to pure GML as they become more advanced and begin to use large pieces of code-- if the handling of DnD blocks, especially the "execute code" block, permitted the various non-workspace options allowed when working in pure code. It should be possible to pop out the content of a particular block into its own full tab or window (the latter, ideally, supporting the improvements discussed above), instead of being forced to work within a sub-area of the window or tab for the event.