Welcome, Julie!
We are a two-adult, zero-child family and we have done three WDW trips in the past 4 years--with three trips planned for this year. We also don't do spa stuff and don't care too much about dining. We like good food, but I'd rather go out for a nice meal at home and eat more "utilitarian" in Disney because food is rather expensive there. To really experience the parks, I would plan 6 days--two each at Magic Kingdom and EPCOT and one each at Hollywood Studios and Animal Kingdom. That's enough time to see everything and really decide if WDW is a place that your family would enjoy doing again. If you use park hopper, you may be able to do fewer days and still hit the highlights, but this really depends on your energy level, how crowded WDW is at the time you visit, and the amount of pre-planning that you do.
Staying on property is great and Disney transportation makes it easy for you to navigate the entire WDW property, but if you are going to Universal, you'll probably want to rent a car (as opposed to taking a taxi). Resorts in the Downtown Disney area will probably be your best bet as they are the closest to Universal. If you stay on property and rent a car locally in Orlando just for the days you need, you can still use Disney's free Magical Express service to and from the airport. It's about a 30-minute drive from MCO to WDW, so this is a nice benefit. If you do rent a car, take advantage of the opportunity to get off property for groceries and/or a few meals and you can nearly make up the cost of your rental car!
I'm personally not a fan of the Disney Dining Plan unless you get it as a free promo (which is often available in the fall) because it is too dessert-heavy for us. Gratuity is not included and what I pay in gratuity at a table service restaurant is sometime almost what I would pay for us to eat at a counter service restaurant!
As far as rides, there are relatively few "thrill" rides and according to others (I'm a non-roller coaster rider, but I have ridden all but 4 rides at Disney), they are not terribly thrilling relative to Six Flags, Kings Dominion, Hersheypark, etc. Each park has 2-3 "thrill" rides and what is an adrenaline rush to one person may be a pleasant ride to another person. A lot of the thrills on Disney rides come when you let yourself be immersed in the show elements of the ride. Some have relatively little motion, but are psychologically thrilling. In total number of attractions, Magic Kingdom has around 25 + fireworks, parades, and live shows, EPCOT has 10 + 11 country pavilions (5 of which have a ride or movie) and fireworks, Hollywood Studios has 11 + street entertainment and fireworks, and Animal Kingdom has 11 + a parade.
Most likely your husband's assessment of WDW as "lame" comes from his age at the time. I've heard a lot of older kids (especially boys) and teens express the same sentiment when they visited at that age for the first time. I would encourage you to pick up a book on the backstory of WDW--The Imagineers Field Guides are good and so is "Walt Disney World Hidden History" by Kevin Yee. All are available on Amazon. The parks change constantly, so some information may be out of date, but these books really help to build excitement for the trip and help you to understand how much detail is really in the parks. It's so well done that it's easy to take some of the finer points for granted!
Hope some of this is helpful! Good luck with your planning. Please keep chatting with us if you need more help with details and logistics!! 