I agree the buttons Apply, Ok and Close are confusing, particularly since Ok is the same as Apply + Close.
I was under the impression that is the standard convention, but okay...
I can't claim I am any good in GUI design, but I have made my fair share of mistakes and had my discussions. So I just want to outline the challenges:
It doesn't do to suggest a GUI which is better for your use case - other people have other use cases. For instance, using real weather is just one possible way. I pretty much never do that, I always take 30 seconds before a flight to configure what weather I'd like to have. Also arguing 'most people use AW anyway' is bad - we don't know that, and judging from screenshots posted, I don't think it's actually true. If you want to automatically start AW and have no METAR, you need to define what's supposed to be happening then.
It also doesn't do to add an option for every special use case - this makes for a confusing GUI - one design requirement for the main weather GUI had to be simple.
Finally, what's intuitive for you isn't for the next person - see above.
So don't turn this thread into 'this is how I would like to have the GUI' - that's not going to translate into a case that will change anything. If you think you can do better, come up with a GUI that's intuitive for a large number of possible use cases except your own.
And "Automatically restart Advanced Weather for each METAR change".
Why on earth would I want to have that behaviour? It defeats the purpose of the whole system to not change the weather everywhere but only at the reported location.