This is a question, not a criticism: Doesn't this just lose hard to ramp? Opponent drops a From Beyond, they're getting to Ulamog and there's very little at first glance the deck can do to stop them. They're gonna have more ramp than you have land destruction in any case.
I think it is more of a fun deck than anything. This loses hard to ramp and aggro from a glance. Mid-range though...this could be brutal against them.
Yeah, I think it depends on the draw. Myr, and languish help a ton against early aggro, as do disperse and visionary. They'd need a pretty great draw to get past my early defenses and probably trample, but there's no doubt that some RDWs would run rampant against this build.
Against pure ramp, I'm less certain tbh. I think if I play first I win, if they play first it depends. Regarding their ramp spells, it depends heavily on which spells they are running. Destroying their lands may be sufficient if I can keep them below 7 - there are many ways to recur moss in this deck, I just need to see 1. And of course, this deck is perfectly comfortable playing as just a pure ramp deck. It's not really missing any of the important ramp cards except for from beyond, which is tbh of dubious value, IMO.
But, what Kryder said, it's just for fun. I think it's probably relatively competitive, I think it will wreck non spike decks, and in general, when it works you get to troll people to death, which was the whole point.
Edit: btw, the fact that this deck is tier 2 or worse pretty much proves moss isn't OP. If it were, a deck like this would be tier 1. Fwiw.