Separates or Integrated? What makes more sense?

Given space is not a constraint, at that price point, I would opt for separates. That would provide for flexibility down the road regarding system placement and changes one might wish to make.

Everyone will choose differently. You have many choices for that price including many top notch sounding integrated amps available these days.  You might not appreciate the ease of an integrated currently but may become a bonus someday. 

I guess the question I have is if a 5k amp and 5k preamp going to sound appreciably better than a integrated which cost 10k?  The ability to build my own amplification combo by mixing and matching is attractive.  On the other hand, good IA have an inbuilt compatibility.  Are Integrateds overpriced because of all the extra engineering and design, and is this compromise affect the sound.  

No, I would not get one like Pass or Luxman. Come on. Get serious. That kind of money, I would get something good. Which coincidentally is just what I been working on. Which also coincidentally was exactly $10k, but I notice just now they raised it to $10,995. Whatever. This absolutely positively cannot be beat with any combination of separates without spending a lot more. Which is why I will be getting it.  Some day....

Behold. The Raven Reflection MkII https://www.ravenaudio.com/product/reflection-mk2/

hypothetically how would you choose to spend that 10k if sound was your main criterion. 

There is no hypothetically with me, not where sound is concerned. Sound quality is always my main criterion, and that means getting the most for my money, and that means getting an integrated. https://systems.audiogon.com/systems/8367Man that Reflection is gonna look even sweeter than the Melody.

I would go with the Luxman integrated.  I would listen, take a look-see, and then buy.