Having the activated abilities of lands cost one less is outstanding
Thopterist was often a two-mana Pia and Kiran Nalar, playing roles similar to those of Lingering Souls in a variety of matchups
Im more and more interested in scalable designcards that have a modest initial mana value and effect, then have an additional, more expensive ability to have a splashier outcome
This last ability shoudn't be used in most games, but it can come in clutch when you need one more mana of a specific color
Remember, the market fluctuates, and prices change
Theres no other mill support though (just Jidoor, Aristocratic Capital and Hope Estheim), and its absurdly slow to activate