You can tap any untapped creatures you control, including creatures you haven't controlled continuously since the beginning of your most recent turn, for Orphans of the Wheat's ability
These were generally cards that were seen to be too problematic when you always had access to them from the command zone (Rofellos, Llanowar Emissary is a great example, as it could consistently come out on turn 2, or even turn 1 with a particularly spicy hand!)
They played well, so we upped the number of changeling creatures
Opening newer sets with their fancier rarities, friendlier holo rate, and more playable cards is great, but it cant recreate the feeling of opening these packs
Domain gives you a scalable benefit based on the amount of different basic land types you have at a given time
Ugins Mastery helps with card advantage, too, but helps you get those hard to flip manifests sorted out by way of an attack trigger