I definitely think it's worth reapplying. After 7 years, your experience should be more important than your transcript. I would make your SOPs very school-specific and clearly indicate exactly what you want from them, what you can contribute, and how your experiences fit your future plans. In terms of the bad grades, I think the best bet is to be upfront and explain, and then show how you've succeeded in areas you may have failed classes (for example, quantitative work you've done since graduating). Having a really strong GRE score will also help you-- admissions staff at SIPA told me that if an applicant doesn't have a very obvious quant background they value the score more.
I think it also matters which schools you apply to. I don't have any inside knowledge, but the two you mentioned (SAIS and SIPA) don't have reputations for being super holistic in reviewing applications (that doesn't mean they aren't, just not their reputation). In my experience applying/talking with admissions staff/meeting students, two schools that are quite holistic in their approach and accept applicants with varying backgrounds and academic histories etc. are Fletcher and Chicago Harris. Check those out!