I like this take on G/W Ramp a little better, but it definitely needs to be tweaked for Faeries. I think we have pretty good anecdotal evidence that Path can be bad in the mirror. I could see O-Ring being a decent inclusion.

Does this deck beat Jund Ramp?

Your criticism of the card is justified, why play a two card combo on the off-chance you pump ridonkulus mana on a turn for a big spell? Especially when said mana can result in a crippling blow of card disadvantage and tempo loss by just bouncing/blowing up the enchanted land.

But there’s another problem that people also don’t take into account when playing the Garruk+Fertile Ground combo, and that’s tunnel vision. This is something that causes folks to be overly focused on/dependent on the mana production combo in order to get things done. This however, over looks Garruk’s innate card advantage engine in its beast production, 9 power worth of creatures is nothing to sneeze at, especially if said 9 power comes from only one card, but requires 3 to get rid of. (Maelstrom Pulse being the exception, but that’s just a reason why the pulse is good) Garruk can admirably stand on his own w/o ramping for mana by just pumping out creatures like an Elspeth with an Expiration date.

In a Jund Ramp deck I play with, I have Garruks, but no Fertile Grounds to speak of. Most of the time, I would drop Garruk on 3, and produce a Beast, The following turns, I probably produced more 3/3s which put increasing pressure on my opponent, especially since most of them didn’t have a Caldera Hellion or Firespout in their 75. Granted, my Jund deck was geared much differently than yours, and thus played a little different.

I guess I made that long winded post to suggest you cut the Fertile Ground, while keeping the planeswalker. I suggest going with the Jund Ramp package your already familiar with, which in my opinion should work out a lot better than the enchantment based ramp.