Viability of quickly farming ender eyes from pre-1.8 villager trades
Eyes of Ender cost between 7 and 10 Emeralds each in Minecraft 1.7.2. In a random seed run, you don't know how many eyes you'll need to both find and complete the portal, but for the purposes of the math, the current pre-1.9 any% random seed world record gets 11 Eyes of Ender.
In order to buy 11 Eyes of Ender, you'll need between 77 and 110 Emeralds, all with limited trade possibilities for acquiring emeralds.
This is not viable in a speedrun, let alone not optimal. In 1.7 trades, 77 Emeralds is 1,386 Wheat at 18 each, 1,078 Raw Chicken at 14 each, and similarly high values for all other trade possibilities.