traveling with a big group requires some planning in terms of your meals especially if you re on the dining plan
Big groups do really need advanced reservations. One thing I noticed was that each restaurant appears to have a "max reservation" meaning if your party is over a certain number, you need to call the restaurant directly. I believe they gave a really high number (like over 20). Ohana is a great option, especially for big groups, but my family tries to stay away from the Magic Kingdom resorts. I guess its the age of our group.
Disney food is overrated? I understand the cost problem. My family has gone "off grounds" multiple times and besides the Ale House, the rest of the options are chain restaurants. That's why we also usually skip Rainforest Cafe. There are three in the Chicagoland Area.
What do people think about the dining options?
At Magic Kingdom an overlooked gem (IMHO) is the Plaza Restaurant. Reservations are not hard to get and the food is underrated. Plus, you can feed a family of five for less than $80 including dessert. Not bad for in park, full service dining.
At Epcot, you did well to point out the nearby Boardwalk area. Just a short walk away you can take a break from the crowds, relax, and grab a No Way Jose at Beaches N Cream!
I second your Prime Time Cafe choice at DHS. Food is good, service is fun, and the prices are decent.
At DAK, the Yak & Yeti counter service area is a great deal. You get sit down quality food at quick service pricing and speed.
Above all, and as you stated, folks should never forget that dining at the resorts is generally easier and better than dining in the park. Taking a midday break and heading to a resort for food is one of the best ways to keep your hungry family happy, healthy, and harmonious!
For DHS, I'd also recommend making reservations at their table service restaurants with the Fantasmic! Dinner Packages. The package gives guests reserved seating in the stadium, and can save as much as 30+ minutes that you would ordinarily need to stand in line to get a decent seat for the show.
I do like the new online reservation system (very much like Open Table), but I feel that some of the more exclusive experiences can be difficult to find if you don't know where to look. Also, the website is still a little clunky and can be slow to load, causing some guests to miss very popular ADRs because the site gets slammed.
I'd also like to give a little publicity for the WDW buffet restaurants. Many people think they're just food troughs for the obese, but I've found that many feature some really interesting dishes and are relatively well maintained considering the circumstances. I would rate most of the WDW buffets well above the average Golden Corral, Ryans, or Sizzler (if they still exist). For guests on a budget, the buffets offer a meal to fill up so you can just get snacks and small counter service items while in the parks.
On our last trip, we tried to make a reservation one particular morning for 1900 Park Fare but there was nothing available. We checked again on the day of, still nothing. My wife called up and they said to come on over and they could squeeze us in. Sure enough, we got there, waited all of 3 minutes and suddenly our group of six was sitting at a table, eating delicious breakfast food and posing for pictures with the characters.
So in short, when all else fails, pick up the phone!