It was a really woeful game - Chelsea have been cack for most of the season. It was Lukaku's individual brilliance that decided that tie. What element of the game are you giving him such credit for, as to label him a 'mastermind'?
My opinion is that he believes that if he makes enough strange/bold decisions which go against the grain, the odd one will pay off and make him look like a maverick.
Cynical, I know - but he's a man under pressure. Don't doubt he wants to take us to 'the heights' - despite him consistently demonstrating that he is not the right man to do this - but his stubbornness & tactical inflexibility just smack of someone who has a bit of an ego... I mean 'purist footballing philosophy' to uphold, which gets in the way.
Really wanted him to succeed and will remember some times fondly - but I've given my head a wobble and decided that I love Everton more than one man's fantastical bullshine.