Actually, I think there are several threads on this forum where experienced LDers talk about the limitlessness of lucid dreaming... Search a lttle more in the archives...
I do believe that lucid dreaming is a gift, but there are proven techniques to things like improving dream control and recall. I've been a lucid dreamer for about 10 years and my mind is tsill BLOWN every time I fall asleep. This may not be that common, but since there are no limits, why think about philosophy only (I think that's a great idea by the way).

Create new worlds

Change your body into living metal.

Arrange symphonies

Go diving on a remote planet in Orion's belt.

Navigate the universe

Kiss the sun

Sing with choirs of angels

Seek the face of God

The possibilities are truly infinite. I think you'll see that many people, though they have been lucid dreaming for a long time, still have a long way to go before reaching an end (is there one?) to the list of possibilities for the lucid ones.