Same answer here as many: It depends.
If you use Extra Magic Hours almost every day, take midday breaks, use the pools, and enjoy some magic touches... you may see more "value" versus all-day park goers who want a bed and a shower, and/or who like to focus the budget elsewhere.
Random thoughts:
1) Sun-Thurs night stays are usually lower rates, and many room specials in recent years have been limited to these nights.
2) Plan on booking room-only (not package). If the room rate drops or new special announced, you can more easily cancel and re-book (or call and have them re-book lower rate)
3) You can hedge your bet and do a split-stay to save a few hundred. I would end at the GCH to have that to look forward to. And you may want to take longer day breaks later in the trip to enjoy the hotel. The morning of change, take an Uber around the park to GCH (or get security escort to walk through Esplanade without searching bags), leave your bags with Bell Services and check into room. If you do it early enough, you can use Extra Magic Hour that morning. And you can use the pools if your room is not ready early afternoon. When room is ready, they will text you room number and your keys are activated. Swing by Bell Services to give then room number and they will be up, usually around 15- 20 minutes unless a busy check-in period.
Example: Arrive Friday, use Magic Morning (if available on your tickets) Saturday at Disneyland (only). Sunday or Monday move to GCH and use Extra Magic Hour at DCA one or both days. Then you have EMH at DL Tuesday, and DCA again Wednesday, if you want. It gets harder as the trip goes on.
Good luck & happy planning