RD depends on what you want to accomplish. Is this a once in a lifetime or every few years trip and you have to ride everything? -- then RD is a must. But if you go often and don't have to ride everything I still feel an occasional RD is just a nice way to start the morning, but not a necessity.
We have only ever felt the need to RD at MK. We find it especially enjoyable to be in an almost empty adventure/frontier land to hop on those rides ( because the masses head towards PPF or MT). Depending up on where you are staying you don't have to get up super early. For a 9am opening even if you are strolling down main street at 8:50 you will still be able to take advantage of the lower RD crowds. To make it worth RD you have to see the value in it -- we want to save MK FP for those typical longer wait rides so we get a lot of rides out of the way with very little waits - BTM, splash, Pirates with 5 minute waits.
RD actually allows you to take an afternoon break and then you can return to the park for the evening fireworks. If you typically arrive late morning or afternoon all you will be faced with is lots of people and longer lines and not being able to accomplish as much.
There is such a thing as Disney adrenaline -- so what you would normally think as impossible at home you are actually excited about at WDW. Like my 5 yo DD staying up until midnight for an AK moonlight magic event. Normally the tired monster in her comes out between 8-9am, but at WDW she was up early, going all day long, late into the night - and didn't complain much at all.
Maybe schedule one RD during your trip see how it goes for you.- schedule your first FP not until 11am. If you wake up and say hell no, you can still sleep in and make your first FP