We did this once for our youngest son's birthday trip. Tons of character meals - almost all character meals. I don't regret it one bit - for that trip and that trip alone. Our son's anticipation of this great fun and endless "choose your own meal" experience (that's what he calls buffets) was priceless. And he did have a great time. But I'd consider a couple factors when deciding.
First, how important is food quality to your family? The only character meal that we think has truly good food is Garden Grill. Opinions will vary significantly, of course, but for us, most character meals range from "that's pretty good for a character meal!" to "wow - that's awful!" When we did all character meals, we ended the trip thinking that Disney food had declined in quality. Then we remembered that this was the result of our own dining decisions, not because the quality of Disney food declined overall. When we returned to our regular dining habits for future trips (which includes a fair number of signature restaurants and no buffets) we were very pleased with food quality! So we are unlikely to have so many character meals in one trip again, but talk to me again someday when I'm a grandmother and I might answer differently!
Second, how much do your kids love characters? Even our then-4-year-old-character-adoring son was starting to burn out after Day 3 - he was meeting so many characters that it became less exciting. Still fun, but we just didn't get the same value out of his response on Day 4 that we did on Day 1. Again, I'm still glad we did it, but character meals were a far more special event when it was just one or two per stay. Really depends on the kids in terms of memories/enjoyment. For our youngest, character meals will likely be his fondest dining memories. But for our older boys, fondest memories are any place with pizza or mac and cheese for the now-17-year-old and signature restaurants for the now-18-year-old.
Finally, how much do you enjoy character meals? If the adults in the group super love character meals, that number of character meals for your trip is perfect! My husband and I have booked character meals for the kids, but we are not interested in them independently. We really value and enjoy a more relaxed dinner and it's a nice break from the parks for our whole family. But if everyone in your group loves a character meal, you have a great plan!
Have a great time!!