Today I read about a protocol called FXP (File eXchange Protocol). Then I thought it is interesting if WinSCP can support it. It seems very practical. I read about it at: https://www.smartftp.com/support/kb/14 (sorry the non-intentional ad) and https://en.wikipedia.org/wiki/File_eXchange_Protocol
I also have one more suggestion: the ability to put the Login/Connection/Key-passphrase screen at background for not interrupt the use of WinSCP.
Again the lots of "Memory access" or "Exception 0000??" errors that crashes WinSCP.
Edit: I read now this post: https://winscp.net/forum/viewtopic.php?t=2911 and thought: "Can FXP be a solution?"