Yes, kind of.
I watched Ozil and Di Maria in the begining of the season and they are much better now. Ozil was brilliant at times but tended to dissappear from games during great periods of time. Now he's more consistent, pulling the strings more regularly, providing pause, he's turned out to be the compass in the team and if you saw a compilation of his games in Germany you will check that he also improved his finishing. Di Maria has also improved, not only he looks more complete individually, he's also more of a worker and solid in the midfield position. I guess they are very lucky to have Mourinho as coach. Not sure if they would have become what they are now with Pellegrini there for instance.
Now, if that's not developing/improving then tell me what it is.
Also consider that pressure in Madrid is massive. Zidane or Redondo were criticized in some patches of their careers there. It's a completely new dimension we talk about.
Benzema has been very poor for one year and a half and has been playing great for months now. He didn't develop either? Come on. It's not a case of red-tinted glasses but glasses alone.
Also, admit that you would have quickly named them all had they failed, so it was always going to be a win-win situation, for you, on your logic of course. Had Canales triumphed and been given minutes you would have said he was doing well at Racing last season.
The way you guys talk it seems players can only be developed in Academies, and they don't get to learn anything past an age.
Also, for the record, what did you say about Marcelo some months ago? If I recall correctly you stated that he would be a failure also. Funny this, last news we have is that he was MVP vs Lyon in a CL round from left back position, and that Mourinho rates him very highly.
OK, the reason why Di Maria, Khedira and Ozil look better now than what they looked at the start of season can be easily explained by the fact that it was a completely new league, a new team, a new tactics, a new coach etc. It has almost nothing to do with the quality of players. Ozil was one of the leaders of Germany NT, and played in World Cup semi-final because he was that good. Madrid didn't do anything in contribution to that.
To talk about their development, you have to have watched what they were before, and I doubt you did.
Benzema? Well, Benzema looked bad for Madrid, but even current Benzema is not as good as what he was at his best for Lyon. I remember watching Lyon matches and thinking "this kid is going to be a Ballon D'Or contender". I may have stated that on this forum as well, I really wanted Barca to get him. IMO, even now, he isn't at the same level what he was at Lyon. He was carrying Lyon to Champions League quarter finals. He was that good.
Your mistake is that you compare what Benzema was in his first year for Madrid and now. You compare what Ozil was in his first months for Madrid and what he is now. It's simply ridiculous.
We may then as well claim, as Barca, to have developed Ronaldinho. You know, that kid was a trouble at PSG and wasn't consistent. We improved him. Would you agree? I think that is not the case, Ronaldinho was brilliant even before and Barca didn't develop him.
One method, not always a good way, but still, is that you can look at how those guys were rated and how much they cost. Benzema cost 35 million euros not because he was a shit kid. He was a beast.
As for Marcelo, yes he has improved at Madrid. That much I will admit, but is that the only one you can come up with?