I don't like names with "master" in them, they are kind of generic and communicate a kind of puerile obsession with dominance, especially in the case of "puppetmaster" and "beastmaster". Also I think they just are descriptively very weak.
At any rate, this job is very clearly what we see in "Hunter" classes. Things like Druid's Soulbeast in GW2, Hunter's Beastmaster in WoW, classic Hunter subclass Ranger archetype in DnD (Drizzt), etc.
I actually think it is quite ridiculous that they didn't just call the job "Hunter". Zidane may be nominally a thief, but between his sword-staff, status-effect weapons, and "Killer" skillset, he very easily passes as a kind of Hunter/Ranger (and is fairly unique to the series in that respect). Plus, in my opinion, people associate his character more with the "Festival of the Hunt" and the killer soundtrack (there is a track called Hunter's Chance) more than the flavor text of a single weapon.
As far as I care, this is the "Hunter" class and should have been called Hunter.
* I don't think the snake motif communicates Zidane at all. Zidane is never associated with snakes, and his trance form is more "beastlike".
* I think it is fairly unnecessary to the job fantasy. I think it unnecessarily limit's the job's aesthetic to "snakes" when it could have been about more than that or something more primal/bestial.
* I think the term "Viper" is a really weak flavor connection to the weapon, as (1) if this is not a poison dot class then the name feels more arbitrary, and (2) while it may loosely relate to having two swords, I think that whole metaphor falls apart when this is the combining-sword-staff job (how is sword-staff "viperish" at all? While I could grant darting in and out as being viperish, windmilling isn't in the slightest; why isn't this a Hunter with Viper/Hawk stances instead?).
Not to mention, if they *really* wanted a name that coalesced "Thief" and "Ranger", as well as give people a clearer "Corsair" fantasy, "Hunter" would have been, imo, more appropriate. Because what follows from the name "Hunter" is a "Treasure Hunter", which would bring in a nice little bit of Locke Cole thievishness to round out the class, as well as better reflect the expac's "gold" theme.
Overall, imo, it is a fairly weak job design. I think in settling on this Viper name, they pivoted too hard into a really shallow, narrow "snake" motif that imo dilutes what could have been a class that was not only more archetypal/expansive, but better reflected the unique strengths of Zidane's whole character. I mean come on, an ancient, low-magic "Hunter" class that used dynamis would be the perfect way to implement Zidane's trance and Dyne (literally, dynamis) skills. Instead we have this weird poison-snake motif just to be edgy (as well as slap Ninja and Sage players in the face) and I hate it.
And finally, as a matter of archetypes, I think people wanted a "Western" counterpart to Samurai and Ninja as a striking/scouting class. And frankly, "Rangers/Hunters" *are* the "ninjas" of the West, as a matter of their general mythos and role as kind of lone-wolf, transient combat-masters. *That* job fantasy is the perfect counterpart to Ninja; this...is just a fever dream. I will forever be wondering why the Hunter has such a stupid name while Ninja isn't called "Froggy".
Weak concept, with the name just kind of encompassing and reflecting a deeper dearth of creativity and polish. Feels like some single-gimmick shovelware out of a Korean MMO, not a well-faceted Final Fantasy XI/XIV class. Snake was the wrong way to go.