If you are going Deluxe (I assume so, since you stayed at Poly last time), here are my choices for you:
1.
Contemporary OR Bay Lake Tower:
I know a lot of people don't like this hotel, but I think it's really cool, ESPECIALLY for boys. The monorail is cool (boys usually love trains...), the newly refurbished pool area is really nice, with a cool slide that both boys will love as well as a new "tomorrowland/futuristic" themed kid's splash play area. The ability to rent boats there is a plus. There is a fantastic beach (just as nice as the Poly, in my opinion), with hammocks and a lot of space for "sand play". There will be a playground opening on September 1 (a brand spanking new one!). Plus, Chef Mickey's is there, and the whole vibe inside the Concourse level is fun. Contempo Cafe (the CS restaurant) has really good food and they provide coloring pages and crayons for the kids.
And, the BEST part about Contemporary is the SUPER SHORT WALK to Magic Kingdom! Can't beat it! I love the Contemporary. And, if you consider Bay Lake Tower, you can stay in a 1br villa and get a full kitchen, washer and dryer AND a separate bedroom for mom and dad
for just a bit more than a tower room at CR. Plus, you'd get to use the pool at BOTH. This resort (Bay Lake Tower Villa) is the front runner for our family's first trip next spring (our boys will be almost 6 and 4, so very similar to yours).
2. Boardwalk Inn- In contrast to the Beach Club/Yacht Club that everyone suggests, I will suggest BWI. I think the pool here is more suitable for younger kids. I have heard that the pool at BC/YC is really only great for adept swimmers and older kids, due to the sprawling nature and several areas of deep water, not to mention the LONG enclosed slide across the street from the pool... Plus, I am not sure about your kids, but mine don't particularly LOVE the feeling of wet sand on them, either in their feet or in their swimsuits. Going to the beach is a bit of sensory overload, and there's a lot of "I wanna wash the itchies out" going on when the sand gets in crevices where it shouldn't be, if you get my drift. I hear that happens with the pool there, what with the sand and all. It's a large grain sand, and it gets in your suit, and it does not come out easily. I'll leave it at that. That and it's not the kind of sand that you can make sandcastles out of, and that would frustrate the heck out of my kids, in a BAD WAY. So, I think we'll stay away from that hotel, as nice as the pool looks. Just thought I'd provide that info, in case you are not aware, as I was not, and it helped sway me away from that hotel, since I was considering it, and I'm glad I learned those things prior to making my choice! Boardwalk, on the other hand, is just a regular pool, with a fun theme. The slide is fun looking, but completely open, so less scary. There is a really nice playground for the kids (the one at BC/YC is OLD and tiny!). There are hot tubs and a kiddie pool all located in the same vicinity at BWI pool area, not all spread around like at BC/YC. Plus the "nighttime entertainment" is at BWI, so you won't have to walk over there, since it'll be right there! BWI just seems to have a more lively vibe, and seems a bit more luxurious to me, than BC/YC.
3. Wilderness Lodge: My favorite hotel. Although, transportation lacks at times. This is its only downfall (and the smaller rooms). I would stay here in a bunkbed room with the kids those ages. This hotel is great because it's got it all: THEME to the hilt, good eateries, fun kids activities, a kid's club onsite, playground, beach, pool, waterslide, kiddie pool, hottubs, a fun geyser by the pool (that the kids love), ability to boat to MK, watch the EWP on the beach. And, just the whole lodge atmosphere can't be beat. I love it there. However, the rooms ARE a bit small. IF you can splurge a bit, get a Deluxe Room, they come with Club Level and that makes it a better deal, but they still run about $525+ per night. But, you get, essentially, a Junior Suite set up, which might or might not be worth it to you.
We stayed there in May and we loved it - the boys did too! The new pool area is great. I like that the main pool is zero entry. The pirate ship water area is great for kids too! My boys would have stayed for hours if we would've let them. 
