Obviously I don't expect the software to catch every mistake (especially given its record of underlining grammatically correct sentences) but if it could catch things like comma placement that CC likes as opposed to what I consider correct (oh, the joys of British vs. American English), it'd be nice and it'd save me having to facepalm myself so frequently.
And yes, I know that the comma example is a bad choice since CC accepts either the correct or the American usage (

Thanks in advance for suggestions.