For me the missing feature is cancel individual files. Let's say I have 500 files in one queue job and want to cancel one file in the middle. Currently it is possible to cancel all queue job at once only.
Another missing feature is respect of the queue for multiple jobs, as described here.

Can you elaborate, what exactly are you looking for? What would you use it for mostly? Do you need to change an order of the individual file transfers? Or cancel individual files? Please be as specific as you can.

I agree. This option being missing just makes it unnecessarily complicated to manage transfers. The queue should allow more interaction. It's nice that we can move items up or down but that doesn't do me any good if all the files are grouped into jobs! It would be nice to be able to disable that grouping altogether and use a flat queue like FileZilla. I would use FileZilla but it is unreliable as hell. I guess I'll just download old versions of WinSCP and see which one has the right behaviour. I guess I'll just start with 4.1.3

:(

I'm transferring 14 TiB (16TB) between multiple machines in a network.

Because of this missing option, I now have to revert to version 4.1.3 (with all the bugs that come with it, which also means: some files will be obliterated (per bug #2132).

I think we should have control over transfers, including being able to SEE what's going on ....

Thanks for your feedback.
That option was superseded by Use multiple connections for single transfer:
Issue 875 – Allow background transfer operations to use multiple connections
The previous option cannot return as such. But management of the individual files can definitely be improved, if there's enough demand. We will see.

Hard to keep track of group transfers when they (the files)'re not listed in the queue.
seeing c:/files/group1 as the source is insufficient for large transfer with many files / folders, especially if you need to cancel one in the MIDDLE.

... much better option (for us who select it).

Disappeared between 5.8.3 and 5.21.5