There'd be no TIE to increase enthusiasm upward. Enthusiasm stays at 10 until you CT (which, as proposed, had a noticeably lower effect on the game and the drop in enthusiasm).Kind of like how a team starts the beginning of the season. Clean slate, recharged and with fresh goals for the season ahead. Over the season pushing too hard (CT'ing too much), losing, etc, wear down the team.
4 - If you CT and win, Enthusiasm will drop less, maybe half as much Your coach just got your fired up for big game and you lost, suck! Your not quite going to get back up for the next big game the same way if you had pulled off a win in that game.