If anything I think the morale perhaps effects results too much, so suggestions that morale doesn't effect anything to me blows my mind
When you hover over morale it tells you a variety of info, such as happiness with playing time etc.
I remember when morale used to be very heavily linked in with a players form, however, (and I don't agree with this and think it needs re-working) you can have a player in poor form or a striker on a goalless streak... and still be ''very happy or delighted'' under morale as long as they are in a team that is doing ok/winning.