I don't have the new moral thing yet, but moral does not seem to have any noticeable effect in terms of performance or maybe it is random. For example, today I had a player with very poor moral [dark red] in the starting line-up for a match and he got the MOTM award. His moral changed from very poor to poor [dark red to red].
There are probably so many cosmetic things in this game that attempt to trick users to spend or buy that this game can be compared to a scam.