If you're focusing on the part boredom plays in the process, I am almost entirely sure this is simply a matter of personality and preference.
I am the exact opposite when I write. I started out trying to discovery write, and I would almost always get bored. I wasn't invested in the characters or the story because I didn't know what they were yet, so I didn't feel like I was writing a story I'd want to read. Basically, I never even got far enough to do any rewriting.
One the other hand, outlining was fun for me. I felt creative when brainstorming the idea, creative as I was developing the story, creative when I was organizing it, and creative when I was writing the prose for each scene. That last one is important. If you're looking to take a real go at outlining, I'd recommend you concern yourself mostly with writing interesting prose after the planning stages. It might keep you interested. Another plus was the complete lack of writer's block, since I always knew what needed to happen next.
Also, this might just be me, but I can't stand the editing phase. It feels like I've already done all this, so I don't get nearly as much fulfillment from it. It feels like a chore.