It depends on your definition of abc limit holdem. If that means never bluffing, fastplaying strong hands, and check calling with draws, then Cepheus would absolutely crush even under the most extreme rake. If your definition of abc limit holdem is the average player's strategy, then I can't really comment cus I haven't played on Stars in years.
Ev estimation is no easy task preflop, on the flop, or on the turn. Neither is estimating equity realization. However, this doesn't mean that we should give up on these important concepts. It means that we should study these concepts.
Lotsa no limit talk on equity realization, but still relevant:
http://forumserver.twoplustwo.com/15...ation-1375961/
cliffs: yaqh owns another thread.
or you could go on a graphical mystery tour with me:
http://forumserver.twoplustwo.com/15...-cbet-1357289/
cliffs: I went on a math trip and drew some graphs of the ev of the 100% cbet. The 0ev threshold has yet to be determined, though I think it's somewhere below the top of the ev curve.