Doran is a lot cheaper, costing just three mana, gives you access to green, black, and white in your deck, and Doran's ability is always on compared to E
Since there is no linked triggered ability left to return the cards exiled by the ETB ability, those cards are permanently exiled." This works extremely well with undying, persist, other big ETB (and LTB) abilities like Realm Razer, and reanimator decks in general
Bahamut is an iconic dragon that dates back to the very first Final Fantasy , when the Final in the series title was still relevant
It would cost one mana in hybrid / and have en etb draw a card
Loot, Exuberant Explorer, Bloodbraid Challenger, Ilharg, the Raze-Boar, and Emergent Woodwurm are all great at sneaking creatures into play without even paying for them