Just saw this old suggestion as I was about to make a similar one, so I thought I would comment here.
As many mentioned, removing the enthusiasm option from a final would take away some of the strategy, but what if instead we were to add in some "momentum" aspect to the finals. That is if you lose a game by a lot (such as when teams throw the game) then you lose "momentum" and are more likely to do poorly in the next game.
This could possibly favor the home team by giving them momentum after their first win at home, but it could be fixed so that momentum is only affected by large point differentials. You could even make it that a team gains momentum if they almost win the road game (thus incentivizing an effort to at least make the game close). This would leave the strategy aspect in the game where managers have to balance the chance to get an enthusiasm boost, but a potential loss in momentum.
As an easy implementation big finals losses could simply lower enthusiasm and then you wouldn't have to add in a whole new aspect.