Ive enjoyed using undying creatures since they were first printed, but I havent had any strong desire to see Wizards explore that design space anymore
Harmonized CrescendoHarmonized Crescendo and Collective InfernoCollective Inferno - Fire Scores of 8.38 and 5.58, Respectively Creature combat decks often want both of these effects
Yes, we have access to Duals and Moxes, some Elves and Mana Birds, Initiates/Priests (outside of Sweden, at least), and a Prism that Ive never seen anyone play, but once you add in Factories, a Strip Mine or four, Maze, Library, youre suddenly running 25+ lands
PDF templates give you something to work with, and you can find plenty of them online
They cost no mana to play but a player may play no more than one land per turn, and only during the main phases of their own turn
The deck is much less fragile and more interactive