I greatly enjoy playing my alts, which we may as well refer to as "glorified profession mules." Some of them I haven't enjoyed as much, usually pure DPS, and that leaves me with characters like Mirrored.
Mirrored has 525 in both Enchanting and Tailoring. She is currently level 77 and likely will remain in that range for quite some time; I'm just not digging Mages lately. (Maybe if she were a goblin. /pout)
In 4.1 when all Twilight Highlands recipes were moved to other trainers I was able to gain access to all the best Tailoring patterns, which was nice. She's my "secondary" tailor so it didn't open a floodgate of new opportunities, but it was still convenient to be able to actually use all the cloth I could make.
Now, however, she's facing being the gimped profession mule once more; with the new patterns being sold by Firelands vendors after strings of Cataclysm quest chains it's unlikely she will see any new phat epix. So what to do? I could always drop Tailoring for Alchemy, something I've been considering doing for a while anyways. But is there another use?
Of course there is! Tailors will be using their Dreamcloth to make all sorts of new epics and I am pretty sure the supply of threads will dry up quickly as everyone trades in their current pants for shiny new ones. While Mirrored won't be able to make any new epics, she is able to make the enhancements for them! So I am going to be saving up her Dreamcloth in anticipation of lots of upcoming thread business that I don't think my competitors are likely expecting.
Can other professions/lowbies benefit?
Eh, not in the same way. "Left behind" Blacksmiths will still be able to make Belt Buckles, Leatherworkers can make leg patches, and so on but the materials to make these aren't soulbound and so could just as easily go to something else. The materials are much more plentiful and not walled behind a seven day cooldown.
I just wanted to remind everyone to not let a profession be forgotten just because it can't access the ultimate patterns; many still come packed with a lot of gold making potential able to see profit far into 4.2 and beyond.