You are limited with a 2 year old, and they just got rid of the It's a Bug's Life land. I'm going to focus on what's different at DL or exclusive to DL.
1. Agree with most, ride the Dark Rides in Fantasyland, especially those that are not at WDW like Mr. Toads. The Alice ride is also a good one that is not at WDW.
2. Casey Jr Train Ride in Fantasyland. If your 2 year old is into trains, they will love this one. My son was a big Thomas nut at that age, and loved this ride. It was a must do at his age. They do not have this at WDW.
3. At California Adventure, there is the Monster Inc ride which is a fun one. I don't think they have this at WDW. The Little Mermaid ride in DCA is also fun, but I think they have similar ride at WDW.
4. Pirates of the Caribbean is much better over here.
5. It's a Small World. Another one that is far better at
Disneyland.
6. I'm going to add a 6th that is fun. Tow-Maters in Carsland is another fun one for small kids.
Now, here are the bigger kids ones that you shouldn't miss because they are either not at Disneyland or are different:
1. Space Mountain - Very different and way more fun. The one at WDW gives me whiplash and back pain. This one is super smooth.
2. Indiana Jones
3. Radiator Springs Racers
4. Guardians of the Galaxy
5. Incredicoaster
6. An honorable mention is the Materhorn. I don't like this ride because it is bumpy and jerks you around (WDW space mountain reminds me of this). But is iconic of Disneyland and should be ridden at least once.
I grew up with WDW for my first 30 years and was at WDW this December. I moved to CA in 1999 and have been a Disneyland passholder for the last 19 years. I like Disneyland WAY better. It took about 2 to 3 visits to Disneyland to convert me to a Disneyland diehard and even trips back to WDW can't change my opinion. One big difference that I noted from my December trip, is that at Disneyland, parkhopper passes make a difference. Its so easy to do, and you should consider parkhoppers. At WDW, not so much. Also, get the Maxpass if you can swing it. I think you will really enjoy your trip.