This argument pops up from time to time, and I'm off the unfortunate
opinion that both views are equally bad. The reason that we report
luck and skill in EMG is that it helps on the report and comparison of
games and matches.
Suppose you are at 17-17 away or 1-1 away. Loosing 5% matchequity by
bad luck would require a very unlucky game at the first score and
hardly any bad luck at the second score. Using EMG puts luck and skill
on a foundation that is independent of score and matchlength.
Unfortunately the foundation isn't very good.
Every argument about EMG or MWC you want to make about luck may be
made for skill as well. For skill our decision is firmly for EMG. For
luck the argument for MWC is stronger, but it isn't 100% convincing. I
like to have luck and skill reported the same way, and if somebody
took the time to make the code changes to report both EMG and MWC for
both luck and skill in a concise way I wouldn't mind at all.