Hi Mary! I'm so happy to hear that you had so much fun on your first Disney vacation that you're planning another!
The Polynesian is special for lots of reasons. One of the most obvious is that it is one of only three resorts on the monorail route, which makes quick trips to the Magic Kingdom a snap. But did you know the Polynesian is the only resort with quick monorail access to Epcot as well? The Poly is located next to the Transportation and Ticket Center, which means you can take a short walk from the resort to hop on a direct monorail to Epcot (whereas you'd have to take two monorails from the Contemporary and Grand Floridian). Other reasons to love the Polynesian are the super-big guest rooms (approximately 415 feet compared to 344 at the Wilderness Lodge), the cool Volcano pool, and the awesome restaurants on site, 'Ohana and Kona Cafe. When my children were young, they loved staying in a first-floor room with a patio so they could visit with the friendly ducks who call the Poly home, and it was fun to walk out to the beach at night to view the Wishes fireworks at the Magic Kingdom.
You already know that there's lots to love at the Wilderness Lodge, including rooms with bunk beds, which aren't available at the Polynesian. In my opinion, the biggest advantage of the Wilderness Lodge over the Polynesian is the price. A stay at the Polynesian generally runs several hundred dollars more than one at the Wilderness Lodge. Whether the Poly is "special" enough to justify that extra money is a personal decision, and people's opinions will differ. I love the convenience of the Poly, but I can often book a club-level room at the Wilderness Lodge for the same as or less than the cost of a garden-view room at the Polynesian, and in those circumstances, I'll always choose the Wilderness Lodge.
Hope this helps with your decision! Please feel free to ask me more questions!