I use it pretty infrequently nowadays and I admit I didn’t see the startup freeze in a couple months (either I am lucky or they finally fixed it in a recent update), the undo glitch is alive as ever though.
Some other things off the top of my head:
• UI freezes for a second or two when you switch to Fusion tab.
• If you adjust speed in a Fusion node, timeline clip remains the same length, so if you slow it down 2x you can only see the first half. To say Fusion in general is half-baked is to be very, very generous.
• Export location gets reset every launch.
• Can’t copy-paste a node or its settings, in case you want to test between two different configurations.
Even the aforementioned RawTherapee (which is made using Qt I think and which is far from a shining example of usability) is more pleasant to use for me.