While we're here, lets also bask in the fact that the original version of Mesa Pegasus was a rare during playtesting
Choices made for permanents as they entered the battlefield are remembered even after they phase in
We see some payoffs that care about casting spells with mana value 4, that is the mechanic you are supposed to aim for, but in practice, the general Limited advice of drafting a good curve, quality cards, and 4-6 removal spells stands above the goal of drafting around the mana value 4 synergy part
Throw Brawn into your graveyard early, and grant all your creatures trample
Mouth of Ronom and Ice-Fang Coatl become repeatable removal, Phyrexian Soulgorger can be brought back once you've enough fodder to feed it, and if you're really up for the challenge, you can go all-in on the Mill route with Iceburg Cancrix and a series of follow-up Snow plays from the graveyard
The first question everyone asks is about value