Why do you think Mulligans aren't a problem? How many games are won/lost simply on having bad luck on your 1st/2nd mulligans? Shouldn't that be mitigated?
Reality is if this is going to be a spectator sport then there needs to be less games decided at the mulligan phase.
The coin flip phase is a bigger issue for eternal, but I don't think its that much of a problem for standard formats so we probably won't see much change there.