Over the last 12 months and 75ish flights I've only SDC'd 5 or 6 times, but still feel that it is a nice benefit that Delta offers. If they are really concerned with their top flyers taking advantage of them then why not allow 5-10 SDC a year that are an actual benefit to flyer and then the rest under the potential new rules.
Over the same 12 months Delta has cut back the number of flights on the routes I fly and increased the cost of the ticket so without status there is no difference between them and the other airlines. If I were to start my flying today it would be really tough to start any loyality towards them.