@DaveW:
I shall agree it is a common misunderstanding, but I think that is due entirely to people mistakenly thinking that sentence is somehow connected to the prior sentence. However, it is a completely separate sentence and lacks any conjunctions to connect it to the prior sentence, as well as lacking any mention of repetition itself. There is nothing to suggest you gain it more than once. I think that is clear once you take a careful look, but I agree that it is very easy to overlook. Regardless, the misunderstanding does occur. Below I have commented on some of Mithror's suggestions to help alleviate this confusion.
@Mithror:
1. I think the reason it wasn't given the Life +2X trait up with all of the other traits was purely due to space. I agree that it would have been a better solution though.
2. This would significantly change the way the spell functions. First, it's Life would no longer be tied to the number of crush tokens. Meaning it could gain Life without gaining tokens, and vice versa, as well as being able to lose tokens without losing Life. Currently there isn't really any way to manipulate token gains/losses, so this is a bit of a moot point, but it is theoretically possible. It also changes the interactions with Finite Life by cancelling the Life gain entirely instead of simply suppressing it. Although that is easy to fix by changing your suggestion to Life +2 instead of just gaining 2 Life.
3. X is already defined on the card as the number of Crush tokens, but you are correct that we could have used this information directly in the Life trait of the card. It's Life could have simply been listed as 6+2X. This is actually my favorite solution thus far for people who wish to clarify the text. I think it would be much less likely to cause confusion, and I think it could be fit on the card without too much trouble.
4. Another option that I think would keep it from being misinterpreted would be to simply move the sentence. Move it to become the first or second sentence on the card, before it starts talking about each upkeep phase, and people will easily be able to tell you only gain it once.
I don't think we'll actually see any of these suggested errata though, nor do I think they are necessary. I do however think that we need clarification in the Rules and Codex Supplement, both to correct any misunderstandings and to explain how exactly to deal with a variable within a trait.