Hi, Melanie!
Two whole weeks in Walt Disney World at any time of the year is magical; THOSE two sets of dates you've provided in your question will be even more so!
For crowd levels, I check touringplans.com, an unofficial crowd-predicting site that's proven very useful over the years. According to touringplans, November 8th-22nd should have averaged crowd levels of 1 out of 10 to 5 out of 10, with the exception of Friday and Saturday, 11/8 and 119 (Wine and Dine 1/2 Marathon, 8 out of 10) and Saturday, 11/16 (7 out of 10.) The first two weeks in December, however, average 1 to 5 out of 10 each day, 9 of which are estimated to rank 1 or 2 out of 10. Crowd-wise, then, the first two weeks of December win.
Weather-wise, patterns can change when dates are so close together, so I wouldn't allow the weather to control which of these two dates you choose for your trip. (We were in Orlando the last week of March and it was very chilly; 9 days later, I returned and it was gorgeous and warm. Happens all of the time.) Either way, those weeks will make great park touring days, as it should have begun to cool down from the heat of September / October, but the real chill of mid-winter will not have arrived yet. Great cholce!
One thing to consider, too, is if you'd like to visit during the
Epcot International Food & Wine Festival, which runs through November 11th this year. If this intrigues you, then the added crowds over that weekend will a small price to pay in order to enjoy the Festival. If not, I'd stick with the early December visit instead.
Happy planning, Melanie! Send more questions as you think of them; we love to help!