The way I see it, Vetruvian is in the same place now as Vanar was last winter.
Vetruvian's identity has been boiled down to one solitary deck; Obelisks. While this one deck has been enjoying relatively high success, Vetruvian is left as a sort of one trick pony, able to only make one decent deck. When structures manages to work, it can give top-tier decks a run for their money. However, if the opponent happens to play a ranged value generator before you can set up your pillars, then you are as good as dead. This weakness had been planted in the faction by the developers through the siphon nerf. However, the Bloodborn expansion did little to alleviate it (all ranged options introduced here cost 5 or more mana) and no compensation was added. Other themes in the faction, such as control, sabotage, and General support, are all but extinct.
This is very similar to the Vanar decks of late 2015. At that time, Vanar was easily the worst faction due to their weakness to AOE removal. If the opponent happened to have Tempest, or Plasma storm, which were not uncommon at that time, Vanar automatically lost. The only viable Vanar deck was a mid-rangy-controlish-vespyr-thing, and several faction themes, such as walls and infiltrate, were more-or-less dead. This parallels Vetruvian's current situation in that the faction is limited to only one deck archetype and possesses a glaring weakness that is commonly found in the meta, being ranged threats and AOE respectively.
Right now, Vetruvian has managed to squeeze out one successful deck, but it's being held back by their lack of ranged removal. Sajj has gotten a ton of support, but cannot survive in this meta. Sajj trades health for Value and health is so valuable in this meta, with all the aggro running around. To make matters worse, Sajj has no reliable options to regain said health other than a 6 drop.
I'm still hoping that either expansion 3 or a balance patch will give Vetruvian a much needed boost. Right now, it relies on one mechanic, obelisks, to stay alive. While the Obelisk deck is really fun, it feels bad having all other Vetruvian experiments crushed by Meta decks. I hope Vet gets some sort of healing and/or some way to deal with things at a distance in the future.
I would Argue that the Bloodborn Expansion did little for Vetruvian:
Nosh-rak: Arguably the best of the grandmasters. It turns every minion you have past 7 mana into a huge potential threat
Autarch's Gifts: A theoretically great card. However, in the lategame, you are ususally very low on health and are thus unable to benefit much from the artifacts.
Incinera: A decent card. It allows Sajj to run away/ pursue the enemy better but it comes out too late to combat ranged threats effectively.
Divine Spark: This spell is largely outclassed by neutral options such as Sojourner, Spelljammer, or L'kian. To make matters worse, the design is rather bland.
Zephyr: His ability, while powerful, is super conditional. Your opponent must have multiple units around your general and you must have your BBS active for this to work. This makes the card very easy to anticipate and rarely useful.
Stone to Spears: Every faction needs one or two unplayable cards. At least the ability to more Obelisks is interesting enough.
In conclusion, ROTB gave Vetruvian powerful lategame, but no way to gat to said lategame other than a very situational board clear.
How I would change these:
6 mana Restore 5 health and equip two random Vetruvian Artifacts.
The artifacts are much more useful if given some health to spare. Compare to Trinity Oath and Aymara Healer
4 mana, 2/5. Whenever your general deals damage to a minion, restore that much health to your general.
An effective way for Sajj to heal. Compare to Keliano and Scintilla.
3 mana, add two Stardust to your hand
3 mana deal 4 damage to and dispel target minion
Versatile, though inefficient, ranged removal for Vetruvian that requires a turn to set up but is quite powerful in the lategame. Compare to Chromatic cold and Onyx Bear Seal.
All of these ideas are just that; ideas. However, I truely hope that Counterplay expands on Vetruvian's identity in upcoming patches or expansions. The Bloodborn expansion did not quite stimulate Sajj the way it did with other underplayed generals, such as Lilith and Starhorn (Kara and Kaleos also did not see significant boosts and Zir'an's boosts, while helpful, may have benefited Argeon more than herself , but that is another topic for another time) but I still hope that Counterplay can diversify Vetruvian the same way they diversified Vanar a year ago. Since they have succeeded in dragging Vanar into the daylight a year ago, I am hopeful that they can do the same with Vetruvian now.