Into Nothing

I recently listened to a friend of a friend speak about the spiritual side of Yoga. He has been working at it for 30 some years, and explained the basic sequence of the practice:

1. Yama, our attitude toward our environment.
2. Niyama, our attitude toward our selves.
3. Asana, body positions (what we usually think of as Yoga).
4. Pranayama, breathing exercises.
5. Pratyahara, quieting our mind and body.
6. Dharana, focusing our mind on a single object or thought.
7. Dhyana, meditating without being conscious of it, only knowing that you "are".
8. Samadhi, becoming one with everything or one with the universe.

According to Yoga, Samadhi is perfection - you can't get any better than blissfully being One for eternity. We are all endlessly reincarnated until we let go of our identity at which point ... into Nothing.

I have some problems with this. First, I don't think we were given the ability to be individuals or to think or grow morally strong if we were meant to melt back into the Divine.

I think this going back into the One was originally put forth to counter the idea that eventually this earth will be destroyed, and we as a race will have no lasting impact.

Yoga is certainly not the only religion or spiritual path that sees dissolving into the Universe as the final step to perfection, but is that the true path? Are there other ways to be eternally happy? In the Mormon religion, when we are old gods, with nothing left to do, will we let ourselves dissolve? Is the timeframe the only difference here?