There are only two workable options: either we are a UNITED kingdom of 60+ million people, each with an equal individual vote, or we split however many ways and consider ourselves to be 2, 3 or 4 separate countries.
I actually agree with you on this point. The problem is we're currently a hybrid of the two. If there was no Scotland, England, Northern Ireland and Wales ( no Scottish parliment or Welsh assembly, no England or Northern Ireland national teams etc) and just a United Kingdom then the current 'everyone has an equal individual vote' would be fine.
However most of us think of ourselves as Scottish/English/Welsh first and British second or not at all and while that's the case you'll always have divison.
Even if we did become four completely separate nations (and just imagine the protests of those who voted not to split but end up in the sizeable minority), you would still have inequalities within the resulting nations as populations still tend to be concentrated in relatively small areas. Would you give the combined population of each settlement exactly the same political weight? i.e. if Glasgow overwhelmingly votes in favour of something but Alloa and Ullapool vote against, then their decision goes for the whole country because 2 out of 3 settlements wanted it?
Obviously not, I mean there's no history of Glasgow or Alloa being indpendent nations for one and I've never heard someone answer 'Glaswegian' or 'Dundonian' to the question what nationality are you? If they got together down the line and decided they wanted to go it alone, like Catalonia, then I suppose you'd have to let them have a vote but that's neither here nor there just now.
As for inequalities as you said there'd still be many in an independent Scotland but it would be far easier to work towards eradicating them in nation of 5 million with full government control, than in a nation of 60+ million where those with the majority of the power will never be primarily concerned with you.