The way we've done the deluxe plan is to use it for two table service meals a day, one being a 2 TS meal (e.g., signature, CRT, or dinner show) and the other being a 1 TS meal (which includes most character meals).
The minute you start using it for CS meals, the value prop (if there is any to begin with) vanishes quickly.
And as others have stated, trying to use it for 3 TS a day is too much food and takes too much time.
The value prop is better for kids than it is for adults, especially if you plan to eat a lot of character meals. The flip side, as has been mentioned by PPs, is that kids often find the signatures meals to be too long (these can easily last 1.5 to 2 hours). It's also tough to spread lunches and dinners far enough apart with kids (i.e, picking an ADR time such that the adults are hungry enough for dinner without it being too late for the kids).
That being said, we've used the deluxe plan on two trips and have had good results using it for two TS meals a day, as described above.
On the first trip, we upgraded from free dining and our party was me, DW, DS8, DD2, and MIL.
On the second trip, our party was the same, except it was with my parents instead of my MIL (on that trip, we were treating them and sort of forced into the DxDP because my parents would never have agreed to pay those prices OOP - instead, I told my dad I got a "deal" like on the Seinfeld "tip calculator" episode).
On both trips, it helped that the adults outnumbered the kids as far as dining at the signatures went.
On our next planned trip, DS will be 10 and there's no way I'm paying $100 a day for him to eat. So we'll likely pay OOP with TIW (mostly letting DS order off the kids' menu - which at most signatures is still a very substantial meal for a 10 YO).