OP - We went through the same process - got GREAT advice from the experiences folks here - and changed our buy. Will you save money? Hard to know. I looked at it this way - take the all-in cost of the packaged trip my wife has booked (hotel, parks, tickets), and come up with a cost per day. Then take that same trip, and run it at a top hotel, since
DVC is much nicer than the AoA or CBR rooms we were booking. Then look at DVC on a basis of buy-in plus maint for multiple years, going each year, buying park passes and dining each year.
By the time we worked different scenarios, we were getting about the same cost per day, but nicer rooms, more relaxing vacations and a higher likliehood we'd do family activities outside of Disney or enjoy the non-park features Disney offers at the resorts. The trick is that the multiple years number you choose is arbitrary, and depends on how many times you can go to Disney in a certain window. But we also realized we would go by ourselves with DVC, and do the Run Disney events or a special event, getting more use (although adding travel cost).
You're buying a capital asset that you allocate over a 10-year plus window, plus add in the incremental ongoing costs, to really compare. But for us, we want to be at Disney more, even without the kids, so the math works well enough to make it worthwhile. But if we just wanted to go every couple years, and stay at a low cost property with an "all-in" vacation deal, run through the parks hard every day, and go home happy but exhausted, DVC wasn't a good value.
We quickly realized this decision was changing how we wanted to vacation, and I posted a thread asking others how it changed the way they Disney, confirming what we were thinking. That was really helpful. We're looking forward to getting our contract, and first thing we'll probably do is find a week wife and I can get a low point cost studio and go just for us. We both work from home or remote, and have family to watch our boys, so a little more flex to enjoy and maximize the opportunity to use our DVC.