I got Dragonwrath during Cataclysm. It was a long and drawn out pain in the ass (10 man for the loss, F you too Blizzard!) for guild and I to get, literally got nerfed between the raid lockout where I completed it and the next raid lockout reset. (The next Tuesday in other words.) It can't be transmogrified, to or from.
Legendary weapons are fun to have before they're nerfed. They're fun to get - that is, the act of actually receiving one is fun. Making them? Not so fun. Not being able to transmog using them is lame, and a hideous waste of some really nice art. I don't like the look of DW, but my hunter has the bow and it looks great, and of course the Axe from LK has the best animation in the game, losing that because you upgraded has to suck. Then there's Vala'nyr or whatever the hammer's called with its pretty healing animations. It's a true pity that all those animations aren't available to show off during raids, etc. while still doing actual DPS/heals/tanking.
It was a choice between 1 and 3 for me, I ended up voting 3. That said, I don't feel that this Tier's "Legendary" is so legendary after all, since everyone can get it. Going from 1 class to all classes seems a bit weird.
What I don't like, is the fact that as a heroic raider, I should be running LFR to maximize my chances at the Sigils. I don't and I don't give a damn, since LFR is a huge pain in the ass and I don't need the gear.
I think they should split the Sigils, so that LFR Sigils don't match up with Normal/Heroic Sigils. Then either lower the value of the gem (already lower value on the weapons), make them taker longer to get or remove "Legendary" quest items from LFR, or maybe as someone suggested, only make step 1 of the chain available from LF.
That said, we all know this won't happen. Either way, Blizz has decided that everyone should be able to get access to a "Legendary" even through LFR and so be it. There's not much legendary about this at all and thus I really don't care all that much.
I think that making the legendary quest line extend through THE ENTIRE EXPANSION across multiple tiers is a smart business move on Blizzards part, it would encourage players to stick with the expansion rather than "Oh just got my legendary daggers, bye bye ill brb in 4+ months" Pretty much what our rogue did in DS.
Putting it in LFR will help encourage even more players to stick with the expansion longer is why I support LFR version of Legendaries.
As for moging them blizz stated multiple times they will loosen restrictions as time goes on. They started restrictions quite harsh so they were able to release the epic feature sooner.