Well, do realize the current weather (I'm going Thursday - sweet!) is not usual for California. Anaheim averages 69 for Jan, while Orlando averages 72.
http://www.weather.com/activities/other/other/weather/climo-dly.html?locid=USCA0027
http://www.weather.com/activities/other/other/weather/climo-dly.html?locid=USFL0372
That being said, I would really suggest trying DL. First of all, ride wise it actually has a couple more rides than WDW (although fewer total "attractions" counting shows and walk-throughs). Since all those rides are packed in 2 parks (and mostly in 1) rather than 4, and that park is the size of MGM, you get a neat little package.
Now if going in January, note that Haunted Mansion and Small World will be down until late in the month (when they switch from their holiday versions to the normal ones), so you might want to go early (the first week) or late in the month. I'd suggest early myself, because the holiday versions of those two rides and DL's decorations are really nice. Their parade also is much ,ore charming than WDW's Christmas one, IMHO.
You will walk a lot less, and if on a buget, you can easily stay at a great motel on Harbor for a fraction of the price of a WDW hotel, and be VERY close to the gates. If money is not a huge concern, though, the Grand Californian is worth it, and not much more than a WDW deluxe.
Two big reasons to go: Indiana Jones and the Temple of the Forbidden Eye and Pirates. The Pirates there makes WDW's version look like the coming attractions.
This is THE year to try DL. I've seen the work progress on it (been out there a couple of times this year) and after May, the whole park will look brand new.
Besides, you can fly Southwest from Midway for under $200 r/t!