No one said you have to do the 10 man versions of the raid instances. The 10 man versions are in my eyes, a way for the more casual people to EXPERIENCE some of the content the hardcore players get - with a cost. The gear is downgraded between the two versions, so why complain? It isn't like the 10-man raiders are walking into an easier instance, and getting the same gear.
They've already said that the while their may be some variation on stats, the 10-man and 25-man gear will have the same models. It's just like how you think someone is in T6, but then you inspect them and they're in S3 with terrible enchants/gems.
Also, if someone is THAT casual, to the point where they won't do 25-mans, they usually suck. Next time you're in a major city, inspect some of the people in "casual" guilds (casual doesn't mean you raid T6 content 3 times a week btw, that's in the middle, like my current guild). Their enchants/gems/gear choices are usually terrible. I don't want even MORE retards in my raids.