Valid point

lets go with instead

Alpha (“the upper class”) Beta (“the second upper class”) Gamma (“the middle class”) Delta (“the second lower class”) Epsilon (“the lower class”) Double-Plus (“the superior subdivision among Alphas”) Plus (“the superior subdivision among Alphas, Betas, Gammas or Deltas, but inferior to Double-Plus”) Minus (“the inferior subdivision among Alphas, Betas, Gammas or Deltas”) savage (“a person outside the integrated portions of society, and therefore separate from all classes”)

Your point about a society capable of large scale gene editing would not need a working class is legit. it will be used to thin the populations out to 'manageable' numbers. Then class split based on parentage.

A perfect system and within 3-4 generations completely normal

Gamma is not "the middle class", it's "blue collar".

You don't really need deltas and epsilons in the long run. Unless they are very cheap to have, robots are going to replace them.

I'm pretty soon you can just break it down into 2 groups. Morlocks and Eloi...

Unrelated, this does make me want to watch Gattaca[1] again :)

[1]http://www.imdb.com/title/tt0119177/

In the really long run, why would you need anything other than Alphas?

Because it's the hierarchy that defines you. An Alpha, alone, is indistinguishable from an Epsilon. See Veblen Good; if nobody looks at your rolex it's just a heavy timex.

Once singularity happens, those are obsolete too.