Patch 4.1 will only bring a 1 boss hardmode raid at most.
Even if it's 3 months from now the majority of players would not have progressed very far in current raid content, let alone Heroic modes. Blizzard have already said it was a mistake to launch ToC so soon after Ulduar as many players missed that tier.
Allowing casuals to experience t11 as current content
I don't believe we'll be seeing any major nerfs, but the main step that will allow Blizzard to reach this design goal is getting players better geared through the new 5 man dungeons so they're better equipped to handle them.
If a new raid was planned then it would only make sense for it to be the big announcement for 4.1. Apart from a comment made at Blizzcon there's been no word of a new raid. "But there's always been a new raid each major content patch" is null as they've shown many times that just because something has happened in the past doesn't mean they won't change their MO in the future. They've also shown with Halion that the don't need a "point 1" patch to release a new raid.
But what about the hardcores??
This is why I said no "major" raid. I believe that we'll see a 1 boss hardmode raid which will drop the new trinkets only. This will give people who have cleared all content something to do while stopping them from getting too far ahead in gear. I wouldn't be suprised if we didn't see this new raid on the PTR.
In conclusion, I think we'll be seeing 4.1 live sooner than expected, but it won't be what many are expecting.