"This is my lack of experience showing but in what way are subtle colors more difficult to match"

I only say that because I am fashion challenged! The ancient has more natural colors, say a moss green, pale orange, a pale blue etc. It is only to my eye, perhaps, but I find it more difficult to find complimentary colors to go with that. The colors in the modern are more straightforward I guess.

But that being said - there are many tweeds from Scotland that do go with the ancient, it just takes more forethought on my part. You may find that not to be the case.