Dont understand how the punishment can be less that the one Essien would have got if the ref spotted the offence at the time. If UEFAs argument for looking at it in the first place is "the ref obviously missed it but in hindsight would have awarded a red' then at the very least it should have been three weeks.
Essien apologising should make no difference whatsoever - any insincere tw@t can apologise after the fact if he thinks it'll reduce the penalty he's about to receive. You don't get the opportunity to apologise and mitigate a red card on the field so why should it be any different if the punishment is assessed after the game?