You can book transportation from the airports to DLR. Once there you will not need a car at all (at all the on-property hotels and many of the off-property ones as well). You will need to either get a car or book a tour if you want to get to Sea World, KBF, or any other LA attractions.
DL is so much smaller than WDW that you can walk from the 3 Disney hotels to DTD, DCA or DL with no problems (and like I said from other hotels as well). The 2 parks are right across from each other (in WDW terms, when you leave DL, DCA park is as close or closer than the buses and the monorail are when you leave the MK).
Dining is much less stressful at DL -- no need to book it 6 mos in advance. There are several character meals to choose from, as well as other options. And since DTD is right there, it's easy to grab a bite there, too (as opposed to at WDW where it takes us a long time just to get to DTD).
We love both DL and WDW -- but there is definitely less walking to do at DL. Hope this helps!