Millicent is one of those names that is ahead of the trend - full of consonants, with a (double) consonant ending, so miles away from the frilly, feminine 'ie/y', 'a', 'el/le' ending girls' names so popular right now.
But - as with everything very popular, their shelf-life is limited, until people tire of those sorts of names and move onto the next big thing.
I think Millicent is great, actually. And in another ten years time, names like this will be what everyone will be going for.
It is infnitely better than the utterly over-used, tired, dull, dime-a-dozen Milly. 