Someone upthread mentioned the purchases of a house and car. Even if said house and car cost more than a less-expensive but still useful version would have cost, still, a person needs a place to live and a way to get around. So the analogy to a DVC purchase is lost.
No one needs a vacation to WDW--although I admit that I feel like I need to!--but even if vacationing at WDW is an emotional necessity, no one needs to finance a purchase of DVC in order to fulfill that need.
OP, perhaps you have an iron-clad guaranteed job/livelihood/business and income. If that's the case only you could know how much this will all cost you and if you're comfortable with the payments.
But if you're just asking what anyone may think about this idea--I think it's a terrible idea to finance a luxury purchase, which buying DVC is. Sure, maybe over the very long term you might pay less for staying at WDW than you would have if you stayed at a certain level of resort, but you could always stay at a Value or Mod or off-site. And maybe you'd have a year when you had unexpected personal expenses and you don't go to WDW at all. If you don't own DVC, you just don't go and don't spend the money. But if you own DVC, you still have MFs to pay and even if you could rent your points, that's just another hassle for you.
Also, you mention that your wife isn't a big Disney fan. She may get tired of going to WDW every year after a certain point. Non-Disneyholics are willing to put up with only so much.
In short, no. Do not pull the trigger. There's no trigger to pull. No situation exists right now that's forcing you to make a decision and buy or not buy DVC. You don't have the funds for it. Don't do it. The next time something costly in your house needs to be replaced or one of your kids needs something expensive, you'll be happy you don't have yet another monthly payment to make for a vacation you might not even be able to take in the near future.