Higher sub crossover is a large part of what I was referring to re the sound quality difference. Granted excellent tweeters, good imagining and detail, good higher-mid's, are the same regardless of speaker size. But to my ears a sub has a much less desirable timbre in 90-150 range than that of a 5" or 6" driver found in (good) bookshelf speakers. (Not to mention in that range you can start to get localization issues that can diminish imaging somewhat.) You mention a 100 crossover, but Paradigm's specs for the MilleniaOne's only rate it down to 120?
Don't get me wrong - both the MilleniaOne's and the Focal Dome's have received universally good reviews and I've actually been eager to audition them. Price is the only reason I haven't yet. I haven't been able to find the MilleniaOne or the Focal Dome for less than $350 each in the US. And, there are some excellent full-range bookshelf speakers in the $700 a pair range.
BTW, please post where the MilleniaOne can be had for $250 - I would like to audition them! Always happy to be proven wrong ; )