I think it's good to compare to something like Earthquake. As long as they have less than 6 pillars, it's worse than Earthquake. It suffers from being even slower/more expensive, cripples the user in the same way, and can be destroyed as well. The benefit is that the pillars don't have to be all concentrated in one stack, and it can affect those who use Nova/Immolation. Though in the latter case, they often use their fire quanta before your turn begins.
It seems like another great tool to use alongside Earthquake, Pulverizer, Black Hole, and possibly Enchant Artifact in a Gravity/Earth denial deck. But I don't even know how well it synergizes with them, because the more of their pillars you destroy, the less effective Graviton Pit is. But again, it helps those decks counter Nova.
I think it's probably better if you don't make it affect your side too. If you use this with a mono Gravity deck against a Rainbow deck, you will definitely be coming out worse off than your opponent. Earth has Gemfinders to help out but it's still a weird mechanic that it would be a card which costs 6
![Gravity :gravity](https://elementscommunity.org/forum/Smileys/solosmileys/../../../images/Misc/gravity18x18.png)
to put you barely in the lead.
My final conclusion is that you should you should have the upgraded version give quanta to you as
![Gravity :gravity](https://elementscommunity.org/forum/Smileys/solosmileys/../../../images/Misc/gravity18x18.png)
, similar to a Devourer, instead of draining any quanta from you, and the unupped maybe give you a static 1
![Gravity :gravity](https://elementscommunity.org/forum/Smileys/solosmileys/../../../images/Misc/gravity18x18.png)
. This is balanced to me because the card is mostly only efficient as a Nova counter, and it opens up applications outside a denial deck. I would also lower the cost to 4 | 4, because it needs to be faster or it just doesn't work to its intended purpose.