I think that Real Madrid made a big mistake when they let go to Wesley Sneijder. he is one of the best playmakers today and Real don't have any midfielder in his level.
Yes Real did big mistake by selling play makers and bring Kaka and Ronaldo. They both are good but you can see Kaka found nothing here and he lost his own form too! Real will never understand facts that money wouldn't bring success. They should learn it from other teams!
I think bringing new players is fine but some time is needed to get them adjusted .so may be the new commer can be good for Real madrid fc
A player can plays good in one team, but worse in another, this is a common thing in sports. As for Robben case, Madrid released him because he's too prone to injuries, not because of his skill.