Plus it's very fair, since you aren't taking anything they weren't intending to use against you
As such, while the mana base is fine if you are a brand-new Commander player, if you already have a Commander collection of any size at all, you probably already have all of the lands that Commander 2018 has to offer
WotC can always print another round of promos, and those newer promos might be nicer than the older ones
Lands, rituals, tutors, draw spells all live again, then get exiled
By the time it achieves this form, your opponent might be able to sweep it in one turn before it can deal a second attack
Thus, if you were to choose F for Alpha Guard, you would be able to untap a Forest, but you would not be able to untap a Wald, Forest's German equivalent