1 is misleading - Sailfish has a UNIX security model. On top of that, it has a bit of user data protection, but granted it is lacking proper application sandboxing. 2 is completely subjective. I never patch Sailfish and find it perfectly usable. 3 is incorrect, Sailfish has a global copy & paste. I can select text in many applications and paste them into others. I don't see the store population as relevant at all to the quality of the OS, especially not with android support. I don't think popularity is a factor either. You're on 1.

That one you can't fix alone. You could implement your own security model, but it wouldn't be part of the OS, and so you couldn't apply it to other people's applications. What you could do is engage with the specification and implementation of such a security model with the Mer community though TJC or the Mer git+tracker. Maybe get one together for Nemo. BB10 never offered those possibilities.

But the definition of an operating system is very well defined, even if it has been twisted in recent years by salesmen and shills trying to lock up ever more functionality in their core 'OS' and establish that as the norm. Remember when Microsoft got fined for bundling their Internet Explorer application with Windows?