Don't underestimate Boone's quest. Sure you don't potentially get two suits of power armor and the training and a verti-bird in the final battle, but his story is so rich. Much more than "I know where my dads old drinking buddies are"
You're right; Boone's questline is great, but the Enclave is very special to me, so even if it is rounding up five old horses, it feels huge.
It's just very sad that the Remnants didn't stay together; it's revealed during the end slide that it all ended as quick as it started.
Even worse that Arcade was forced into exile due to his past affiliations with the Enclave.