Dorman has only three seniors also (I think). Regardless - I expect all of those mentioned in this thread, plus plenty of others, to put very good teams on the field.
A word of caution - every year it seems like Mauldin has a lot of impact seniors, only to have more step up the next year. I find that to be true of most of the good PROGRAMS. Counting seniors is not always the best way to predict who will be at the top the proverbial "next year".
WIN NOW!!! Who knows what will happen next year? Move-ins/outs, transfers, burn-outs, injuries, bad bounces at critical times, seniors deciding not to play in order to pursue a college dream, impact freshman (or not)...I could continue with this list. However, I think you get the point!
If you build a good program with a solid club feeder system, then you will probably taste a fair share of success.