We almost always visit WDW in late April or mid May and have seen many people get disappointed trying to get into a decent TS place without an ADR, especially inside the parks.
Character Meals are a definite must-ADR.
TS lunches are easier to get as a walk-in, but TS dinners are a must-book too. We ourselves have been turned away from many places, last year we struck out with Mama Melrose's, 50s Prime Time, and Hollywood & Vine (we were at MGM later than anticipated). Year before that we were turned away from several places in Epcot and from a couple on the Boardwalk before giving up and eating pretzels and lemonade for dinner.
I can totally understand how hard it is to book ADRs for a group in advance, especially if there are multiple adults involved (kids will almost always eat anyplace), but even if you don't want to book every dinner ahead of time, make a note to at least contact Guest Services once you are in the park each morning to secure a dinner reservation - and in that case, be prepared to settle for your third or fourth choice especially on weekend nights. At least that way you can be more flexible on what park you choose each day, but still have arrangements before it's 'I'm starving I don't care if we eat napkins with ketchup!' time.
Having done
DDP and not done DDP several times each, I would say hold on to the CS for an 'early' lunch - and either bring oatmeal/muffins and juice for breakfast or use snack credits for that. Of course, having a later-ish ADR for a character breakfast buffet can be good too. It's just that unless you are doing a character breakfast or Kona for the Tonga Toast, breakfast is kind of a 'waste' of a credit in that the OOP expense for paying for the items would be lower than if you paid OOP for CS lunch (or for 'extra' things to fill in the holes left by the 'snack-credit' lunch option).
