First, I don't think the loan move will drop his value. Right now his value has dropped anyway, I think, any club could bid lower of the value as long as they can promise him the 1st GK position, and Cech want the move. If he go on loan and play a lot of matches and doing great, he will maintain his value on the market, rather than just sit on the bench in here and play only a few games. Second, he will get a lot of match under his belt while going on loan. I think he will be happier. Third, IF Courtois "flopped" this season, hey, let's call Cech back for next season. Fourth, the club who loan Cech will get the top notch service of world class GK. Completely different from your point of view, I don't see any disadvantage in this case, imo.