Him being acquitted doesn't automatically make the complaint false, as anyone with a shred of common sense will acknowledge. Unless she clearly perjured herself there is no basis for legal action against her. Going down that road would be a severe disincentive to report sexual assaults and absolutely not in the public interest.  
There may be a reasonable middle ground but I don't think it's been discovered yet. I know of one case in Alberta where the complainants did make false accusations and perjure themselves, to harm a teacher they disliked. The case obviously collapsed after years of legal process and wrecked the latter stage of his career - no repercussions to the complainants for an obviously criminal act.  In that case the crown should have acted but they played the false complaint out all the way to trial and embarrassed themselves.
Your notion of going after some accusers may be valid in a few cases but I don't think our system is smart enough to get it right.