I'd say the opposite, that
Bianca is nicer sounding and simpler.
The sound of
Blanca reminds me of 'blank', and the meaning reinforces that. Also,
Blanca seems like a word name to me, so the meaning of 'white' is an immediate/obvious association, and that alone would make me feel awkward using it. A meaning of white or blank could be conceptualized positively, but that's not my immediate reaction.
The meaning of 'white' for
Bianca comes across as more abstract to me and doesn't bother me in the same way.