We go to Disney every year, and we love it. I agree 100% that memories are priceless, and I think vacations make the best memories. However.... the OP wrote that they were going into debt over this vacation. Everyone has different comfort zones regarding their finances and debt, but I would never go into debt over a vacation/honeymoon... it seems like a good way to get off on the wrong foot financially in a new marriage.
OP, you'll have to decide for yourself of course, but you may be asking the wrong question (is this trip going to be worth it?), on this forum in particular! I think your plans sound wonderful and I cannot fathom that you are not going to have the time of your life. But what you really need to be asking yourself is will I love it so much that I will be happy paying for it for a year after it's over? And have you considered how much interest you'll have to pay and added that to the final bill?
One suggestion above was to wait until you could afford it.... is that a possibility, to change the dates, maybe go in 6 months or so when you can pay cash for it? Since you're already having remorse, I would be afraid you are not going to enjoy it as much as you should...there is nothing better than enjoying a vacation that is already paid in full!
Even with a $50 penalty to make some changes, it will be worth it to save interest in the long run.
Here are some thoughts:
DDP: We have purchased this in the past, and it is not worth it to us. You have to really like to eat, eat at the expensive table service restaurants, order some of the most expensive things on the menu, and eat dessert (twice a day) plus a snack. I agree totally that dining is part of the experience, and with or without the DDP we love to go to many of the nice restaurants, but that is just too much food for us, and is not worth it for us. You can look at the menus of each of your restaurants, ball-park what you think you would like to eat, and figure up about how much you will spend at the restaurants you want and compare that to the price of the DDP. If you cancel the plan, you can bring granola bars and instant oatmeal, etc (use the hot water from the coffee maker) for breakfast, split counter service meals, bring bottles of water/soft drinks in your suitcase to bring into the parks (you'll have a refrigerator at a moderate resort.) If you do think the DDP will be worth it for you, then use the snack credits or save the deserts from lunch (they are usually in sealed containers) and have them for breakfast, so you won't have to buy any meals out of pocket.
Room: Like others have said, the DDP really is not "free" b/c there are so many ways to get rooms cheaper (Disney discounts,
AAA discounts, etc). If you think you will spend the majority of the time in the parks, then downgrade to a value. We own DVC (paid for with cash!) but stayed one night in a value once the night before one of our vacations... the room was fine, the resort was cute, it was just very crowded.
Transportation: We always use disney transportation... sometimes it's crowded, but even when we're having to stand up, I can see the long line of cars waiting to get out of the parks at night, and feel lucky to be riding the bus! Like everything else, it depends on how much you value things, but that $200 saved will pay for tips (or at least some of it.)
If you want to give the cheaper version a whirl, there's a DIS budget board that will help tremendously. Disney is never a cheap vacation, and it's always wonderful (IMHO)... every penny you spend, including interest, may very well be worth it to you, but you can also have a fantastic, amazing trip without spending so much or going into debt.