I've been using 8.4 for a bit now and here are some issues I have noticed when working with templates:
Those might seem like minor issues but get really frustrating when you start to deploy you own templates. There's a great amount of new features in the new release, but the % amount of jank seems to remain constant 😞
It's good to see critical feedback out here, as opposed to just problems that need solved. I have no idea if anyone from the vRA team hangs around out here at all, but maybe they do and maybe they would take some of these concerns seriously. Who knows....
I doubt much will change with the new paradigm of content sources. That seems like a design decision and would probably be difficult/disruptive to walk back. From our experience, updating the content source never has to be run more than once. And to be frank, it's just a couple clicks. We're not updating our templates all that often, maybe once every couple months - so definitely not a big deal to us.
I think we have seen that external actions may take what seem like 2 cycles of vRO syncs before they show. Or sometimes, I believe, we have had to update the version of the action in vRO so vRA would "see" it as changed. Never fully looked into the when/why for those scenarios, so I might have that wrong.
For cloud templates, we have resorted to setting all of the default values to empty strings (for text fields) so that we can control whether they're required or not in the custom form. I agree that this is a pain point - why not just assume an input is null if it's not passed. Not sure if that is actually be design but does seem silly?
We have found, at least for parameters of external actions on a custom form, that we can set a constant to empty string if we open the yaml and set it accordingly in there. I have not tried that with the default values for form fields, but maybe that would work? Again, agree that the "empty" use cases on custom forms doesn't seem well thought out.
I have mostly found the Update action useless/problematic. I agree that it does not seem to care at all that there may have been a custom form used when creating this thing and that we want to use that custom form again if updating. So we really try to avoid using it. We were hoping it would be like a resubmit from days old, but it really is not.
All that said, we've been rocking with 8.x since December and things are going pretty well. But we dove in pretty hard to prove that we could reproduce the functionality we had in 7.5 with 8.x. It took a decent amount of effort but I'm glad we're through it and on the other side now.