It introduced a plethora of cards that were either too strong, too efficient or just too good when compared to all the other cards of the time
The need to not miss land drops early would leave both decks with lots of land and not that much to do with it, allowing a player with Goblin Trenches to pressure the opponent slowly, go all-in or do anything in between and usually make their choice work
Theres some chance that the desire to play creatures that cost 1R to support Burning-Tree Emissary will keep this card down until Burning-Tree Emissary rotates, but after that this has to be one of the first two-drops red decks play
Thankfully, there are a number of ways around this issue
You can have up to four of any god with the same name in a Constructed deck, and you must follow Singleton restrictions in Commander
Honorable Mention #3 - Nissa's Victory It's very simple