When it ETBs or attacks, you can toss a flood counter on any land and It becomes an Island too, not as a replacement
Ancient Cellarspawn is a cost reducer that adds a great bonus of life drain that puts cost reduction on the map
If you want to complete it yourself, do not keep reading
Worldsouls Rage can ramp you into three or more additional land drops depending on what cards are in your hand and graveyard
According to The Commander Format Panel, "Game Changers dramatically warp Commander games, allowing players to run away with resources, shift games in ways that many players dislike, block people from play, efficiently search for their strongest cards, or have Commanders that tend to take away from more casual games." The Game Changers List dictates some elements of how strong a deck is, by giving guidance on how many should be played or which ones should be talked about
But especially for a green deck that doesnt seem like an unreasonable limit on its power