What happened to all the old guild masters?

[Lucke]

All the 2.0 guild masters are different people then their old 1.0 counterparts. So, what happened to the other guild masters? Did they retire? Were they killed by the calamity? It's always bothered me why the guild masters aren't the same. And what's more, the current ones with maybe the exception of Mylla, really don't even mention the old guild masters.

Where did they go?

[Skies]

Some guildmasters are still around.
The old Armorer guildmaster is still making boats, except he's no longer part of the guild itself, you meet him as part of the MSQ when you fight Siren the first time (and interestingly, his story in 1.0 had you make brass earplugs because you were dealing with rumors of a siren. GUESS WHAT HE STILL HAD WITH HIM).

The actual guildmaster of the old alchemist's guild is PROBABLY still the master of the actual medicine shop, but since the guild has effectively split (most guilds have actively split from their mother organizations) he haven't been mentioned.

The fisherman guildmaster is STILL the same, it's just that the one that does all the guildmaster job is his companion (a thing that was going in 1.0 as well)

Some guilds are left unexplained, yes, although Serendipity (goldsmith) mentions the one retired and the Miner guildmaster mentions she just recently was given the role as the old retired as well.

[Lusavari]

Actually, the armorer, while still the same, is the Miqote outside, where she's always been. The Smith master was Mimidoa (sp).

The Old Lancer and Archer masters are around, but they're not guild masters. You see Godwin from the Archers and you meet the Lancer master in his personal chambers during the Gridania story.

The Conjurer master is actually still where he's always been, the Padjal E-Sumi-Yan. I'm curious what happened to O-App-Pesi though... Also, the Botanist guild leader is still the same. The ones that have changed are:
Miners
Goldsmith
Blacksmith (Still In Game)
Marauder
Gladiator
Lancer (Still in game)
Archer (Still in game)
Thaumaturge
Pugilist
Arcanist (You visited that guild at met the master in the 1.0 story, their disappearance is a major point of the ARC story now.)
Weavers

Ones that are still there:
Botanist
Conjurer
Alchemists
Fisher

No Clue:
Culiniarian
Leatherworkers?
Carpenters (I think it's the same guy...)

[Skies]

Oh, O-App-Pesi is featured in the White Mage quests, it appears that he is busier than ever with his duty as a padjal that does not involves the Stillglade Fane.
It serves to remind some guilds were not so much guilds but other institutions offering training (Miner's guild was the Amajina & Sons, Archer's guild was the God's Quiver, Lancer's Guild was the Woodwailers), some had guildmaster shifts when the guilds became independant (even if, for say, the Miner's Guild is in a space rented from Amajina is pretty much has offer it's top miners to them to keep independant).

Lusavari has a good list, I think he's got it correct!

[Lusavari]

I'm still working my way through the 2.1 story as I only recently came back... but I've always wondered what happened to the Twin Lalafel miners and the Roegadyn Gladiator. There are 2 Hyur int he GLA story with the same sword as the 1.0 Ul'Dah story Roegadyn.

[Wadoka]

I think there are a pair of twinned Lalafells at the end of the current Miner's Guild story quest. They are members of " The Concern".

[Lusavari]

These guys?

http://ffxiv.gamerescape.com/wiki/Popokkuli
http://ffxiv.gamerescape.com/wiki/Seserukka

[Skies]

I am fairly certain they show up in the last cutscene when you are in front of a council of the Amajina & Sons Mineral Concerns

[Lusavari]

Awesome. Luckily my character I've been playing since I came back to the game is fairly far in the Miner Story. Guess I need to grind her out later.

[Enkidoh]

The Old Lancer and Archer masters are around, but they're not guild masters. You see Godwin from the Archers and you meet the Lancer master in his personal chambers during the Gridania story.

Actually you're getting them mixed up. It's Lewin who ran the ARC's Guild in 1.0 whom you meet during the Gridanian ARR storyline (who has swank chambers in the ARC's Guild to boot) - and in 1.0 he actually did state he was actually the Guildmaster of the ARC's Guild (as well as leading the God's Quiver):

"We meet at last. I'm Lewin, guildmaster here. I run this rabble of chocobos' arses what call themselves archers."

However, given the fact it was revealed much of the 1.0 starting city storylines were actually within the Echo, it's likely in reality by the 'present' day in 1.0 that was probably no longer the case.

The Conjurer master is actually still where he's always been, the Padjal E-Sumi-Yan. I'm curious what happened to O-App-Pesi though...

O-App has returned to the forest for mediation as the padjal often do - its the story reason in 1.0 why Kan-E-Senna and her siblings weren't around at first - they were in the forest in communion with the elementals, and only returned due to the events leading up to the Calamity. And the original 1.0 Gridanian storyline started with E-Sumi as well returning to Gridania in similar circumstances (upon entering the city, an npc exclaimed "Brother E-Sumi is back from the wood". So they frequently have periods where they're out in the forest away from the city. In any event, a level 30ish quest involving Odin features O-App briefly (you speak to him in Quarrymill).

Also, the Botanist guild leader is still the same.

Yeah, Fufucha is still around, although her outfit is completely different to 1.0. But she's at least still Guildmistress of the BTNs Guild.

The ones that have changed are:
Marauder

That's not surprising, given the whole guildhall itself has moved from the Astalica into the Coral Tower. One of the Yellowjackets there actually mentions why this happened (Limsa's government decided to expunge the MRD class of it's 'pirate roots' by giving it an air of legitimacy, hence moving it from a docked pirate ship into the HQ of the Knights of the Barracuda. So a change in Guildmaster would also be natural.

Gladiator

This was the big question mark for me. There is no explanation as to what happened to Yoyobina in 1.0. It's possible he might have retired, be forcibly removed from his position (by a member of the Syndicate annoyed with Raubahn perhaps?) or been killed in the Calamity (Ul'dah after all clearly took damage during Dalamud's fall), but nothing is stated in game as far as I can tell. Mylla doesn't mention her predecessor at all, which is a shame, as I liked him in 1.0.

Lancer (Still in game)

I'm not sure, but from what I understood (I never levelled LNC in 1.0) Swethyna was the Guildmistress of the LNC Guild, but, I think I might be confusing 'leader of the Wood Wailers' with 'LNC Guildmaster'. Having said that, Lewin is likewise the leader of the God's Quiver still in ARR, yet my above quote he clearly stated himself as ARC Guildmaster as well, so I guess the two roles were complimentary, as least before the Calamity. In any event, I haven't seen Swethyna anywhere in ARR, other than this piece of official ARR artwork you can just see her standing next to Lewin fittingly on the far top left side of the image.

No Clue:

Leatherworkers?

If I remember rightly, Geva is still around, yet she's no longer the actual Guildmistress - someone else has taken her place. Having said that, looking at my 1.0 screenshots, Geva was never actually directly stated as being 'Guildmistress', but just as a 'master' leatherworker. Given the other Guilds actually had their Guildmasters shown or referred to though in that storyline, it's likely she really was the LWR Guildmistress.

Carpenters (I think it's the same guy...)

Again I'm not sure - in 1.0 the Gridanian story featured a CTR named Zezetuka, but again he was never directly mentioned as the actual Guildmaster, only that he was elderly and was an actual master of the craft. But again, 'master' and actual 'Guildmaster' are two totally different things. In any event, I don't ever remember seeing Beatin in the Guild in 1.0, not that I ever actually did take up woodworking.