I'm with Wagner. This land requires a heavy committment to Goblin cards to be really good (and it is really good with a handfull of Goblin cards, or after a Goblin Ringleader has hit play), so unless you're playing a R or R/B Goblin deck that splashes G for Life from the Loam, it can't really be broken by that card IMO. And even then it is questionable.
One thing that may have been over the top was the tribal land bit. I still think it's super cool as a tribal land, but it has so many awesome interactions because it is a Goblin that it may be too powerful. It is a mana source that is tutorable with Goblin Matron, Boggart Harbinger and Goblin Recruiter, put into your hand with Goblin Ringleader, and put into play with Goblin Lackey...
Collapsing Warrens
Land
Collapsing Warrens comes into play tapped.

: Add

to your mana pool.


,

, Sacrifice Collapsing Warrens: Reveal any number of cards in your hand. Put X 1/1 red Goblin Warrior creature tokens into play, where X is the number of Goblin cards revealed this way.