I think even during what used to be slow times, it's getting harder and harder to be spontaneous with dining.
Our family is another one that (a) doesn't know what we're going to eat in a couple days, let alone six months away; and (b) due to our jobs, can't book any kind of vacation until about two months out.
How we've still enjoyed WDW:
Book just a couple ADRs, any must-dos for your group. If you have a favorite steakhouse, seafood place or character meal, call and see if they have any openings. It's not to hard to work around one or two dining reservations over a whole vacation -- at least opposed to every day for us spontaneous folk. At this point, you know your dates. If there's any particular meal you just have to have when at the World, go ahead and book it.
Focus on resorts. IMO, the food's better, the atmosphere is better, you're not taking away from precious -- and expensive -- park time, and they're easier to get into.
Don't turn your nose up at the CS. It's vastly improved over the last five years, at least for adults, anyway. And I remember the '70s where you ate CS at your own risk; most families brought in sandwiches. We're to the point where some CS we actually prefer over some TS, i.e., CS at Epcot instead of the TS, Tusker House (soon to be changed, tho), and Pinocchio Village Hause CS over any TS we've had at MK.
Have a bit of a plan if there's just nothing available. We now hit the parks early so that our evenings are free to try new places offsite, go to Citywalk or the resort restaurants at Universal for dinners. At first I was a bit frustrated when there just weren't a whole lot of options on WDW property for a nice-sit down meal for those that didn't plan months in advance. Then I started trying places off site and was extremely pleased. It's affected how we tour the WDW theme parks, but all in all, we've been able to explore off site options and still enjoy the parks in the mornings and early afternoons. We also save quite a bit of $$$ by doing this
