Fun fact, Vetruvian was actually on the border of death Pre-Shim’zar. Vetruvian has the worst core set out of all factions, it’s so bad that for the longest time all Vetruvian minions aside from Aymara Healer were unviable. In those days, it was so bad Vet’s best deck was Inner Oasis Mech and Arcanyst.
Is Vet’s current situation as bad as Pre- Shim’zar? No, not even close. Vet can actually play in-faction style decks(Something that wasn’t viable until Shim’zar) and can pilot these decks to S-Rank. I made it to S-rank with an Aggro Devish list(Funny fact, it was supposed to be a Midrange list with Third Wish but turns out that Third Wish lets you kill people on turn 5…) right after the nerf, I made it to Diamond before the nerf and finished the rest of the climb toward the end, picture proof below. So, no, Vet is not competitively dead.
Personally, I find the whole Siphon Energy situation to be over exaggerated quite a bit. Yes, it sucks quite a bit. But, people were cutting Siphon Energy from their deck before the nerf, around half of the lists I knew of recommended cutting Siphon. And there are ways to counteract a ranged unit, smart positioning and Shroud, Tigers, Third Wish ,and Ankh all are pretty good at handling units from a distance, it may not be as convenient as before but it’s perfectly doable(unless your opponent is Abyssian and sits in the corner surrounded by wraithlings with a bloodmoon.). I normally ever had too much trouble with ranged units as Vet, yes, there are games where I get completely wiped because I never drew Shroud. But, if Shroud is a replacement for Siphon then I would’ve never drawn Siphon and would be in the same position.
However, there’s no doubt in my mind that Vet is currently the worst faction. But that’s mainly a meta thing, right now Magmar is the most dominant faction which is Obelisk Vet, Vetruvian most competitive archetype, biggest weakness. Magmar has a lot of ways of shutting down Obelisk Vet like Natural Selection and Warbeast, but the the card that really puts the nail in the coffin is Plasma Storm which destroys pretty much everything in Obelisk Vetruvian. I’m not sure how standard Midrange Vet fairs, I feel that it isn’t fast enough to contend with the meta and other than that there is Sajj, who nobody has found a truly competitive deck yet. But, something to keep in mind is that the tierlist is actually really close. Vet is slightly disadvantaged over the rest of the factions, but only very slightly. A good Vet player can still make the faction tick.
To my credit, I’m a Vet main with 11 ribbons in the faction and been almost only playing Vet for nearly 10 seasons(I’m taking a break from Duelyst for a bit right now.). I don’t know everything about my faction, but, I believe I know enough so that my opinion at least has some weight to it.