Easter and Christmas are the most crowded, summer somewhat less except July 4 week, and Thanksgiving less than any of the above. If you have not done a peak time before, then yes, it can be a shock the first time after going other times. For example, that January crowd you are used to, and I assume you mean after the first couple days of January which still have much of the Christmas crowd, is about 1/4 the size of the Christmas and Easter crowds. During both of those peak times lines for popular rides can exceed 2 hours for almost the entire day and evening and fast passes run out before noon; moreover, the streets remain very crowded. Conceptually: you are standing at the base of Main Street looking down toward the castle at noon; during January you see people strolling along but there is plenty of space; Christmas and Easter, you see nothing but bobbing heads next to each other and cannot even see the street or sidewalks. Summertime is not quite as bad but the real issue then is heat. Getting ressies for dinner before you go is a necessity.
We have gone twice now the end of Jan. for about 6 days and WE ARE SO SPOILED. Matter of fact the kids always say....we should always come this time of year. Our 2nd favorite is the days before Thanksgiving...about 5-6 days before......then as it approaches Turkey Day it gets nuts .But we have had two nice trips then too. I don't think I could stomach the parks at Easter or Christmas......not after being at lull times and gettind to do it all so calmly. I would however might consider going if we just avoided the parks. Not sure the kid would like that theory though. LOL
Nevertheless, for veteran DVCer's, who have already seen most things before, and always know there are coming back again later, it can be OK. You just need an attitude that you will do what you can and not care about what you don't on this particular trip. Early morning can be a time to hit a lot of things, and then there are pockets of openings for many things during other times of day, e.g., at Epcot and MGM, many things other than the most popular things are fairly easy to get on after 3, likewise for some things at MK between 4 and 8. Early afternoons are a good time to be at the pool during the warm times. If you play golf, the Disney courses are excellent. Good time to hit night time shows such as Hoop Dee Doo and Cirque. Christmas time offers scenery worth seeing , e.g., the Osborne Lights. In other words, you can do fine as long as you have a healthy mental approach.
Grab a book an hang at the pool. Take in the sites and sounds of boardwalk. taking our time strolling through different resorts.
UNIVERSAL 
Congratulations!
