That's only when you're using deferred - you can still use the non-PBR mode with forward rendering!
Also, when you open a preset, you now get to choose which type of shader you want to start out with, it has both PBR and non-PBR as templates :)

It's simply because PBR without specular isn't PBR at all, and thus all the math behind it falls apart! It's no additional cost in the Deferred pipeline either, it assumes all shaders use all parameters

In Unity 5, there's no such thing as non-PBR deferred, except in the legacy deferred system, which is no longer supported by SF. So, you are using PBR :)

This has now been implemented in 1.17 :)

A partial update - as of 1.17, there's a node called Hue, where you input a value between 0 and 1, which will output a fully saturated color in the spectrum :)

There are quite many of them. Which ones, apart from sintime, do you occasionally need?

Does it still happen if you disable auto-update node previews in the SF settings?

I've been trying to do that as well, to get native lit particle support in SF - but it seems like it's near-impossible to grab the fragment position. Is that something the matrix helps with? :)

There's currently no matrix datatype, so that needs to be in place first. We'll see! I can research it today and see when/if it'll make it in

Forgot to flag this as finished, but this has been available since the Unity 5 release of SF :)