The purpose of enthusiasm is not to reward you for your wins.
Which is exactly the problem with todays stupid system that just rewards the better teams that can basically TIE through an entire season without thinking at all and which has no logic at all.
Instead you should be penalized/rewarded depending on how well you maximized your efforts. Anyway, it should have said TIE and big loss can could actually imagine to increase enthusiasm a little rather than just keeping it on the same level(even though I can easily see how this could be missused). Of course other loss changes will need to be updated accordingl.
What it al boils down to is that the skilled manager should know how much effort to put into a game. If he plays normal and looses he wil be punnished. On the other hand if he chooses TIE he want get the same punnishment if the loss is big.
As a trivial example, suppose that a slightly better team wins with a small margin after both have played normal, ad that the slightly better team gets the victory with a smal margin, then the slightly better team will increase enthusiasm compared to the other team. On the other hand if he other team played a TIE and the slightly better team gets a big win enthusiasm will stay the same for both. Finally if the slightly worse tam playes CT and gets a small win the slightly worse team will gain enthusiasm on the better.
Consequences of the current system is that a better team can basically build enthusiasm without really thinking, just as the bad team can, because he will loose anyway. Furthermore enthusiasm can easily be missued.
(However, to be frank, I think the whole enthusiasm bs should be removed completely. Just trying to explain different consequencs of different designs illustrates how weired the system is to begin with)