It seems like earlier in development, Vasari had the ability to deploy phase stabilizers anywhere using a ship item. Due to this, the Antorak's Stabilize Phase Space ability was redundant, and it was replaced with the new Phase Restoration ability. However, the ability to deploy phase stabilizers using a ship item was removed at some point, presumably for balance reasons.
This now leaves Vasari with a pretty glaring gap in their mobility though: the ability to return to a friendly gravity well from a hostile one. This is most noticeable when I'm striking deep into enemy territory on large maps, and someone else attacks my home planets. In that situation, my best option to quickly return to defend my capital is to claim a planet, and build a phase stabilizer on it. This works, but feels awkward, and takes a couple minutes, which is annoying when starbases seemingly can't hold up against even a medium-sized fleet for more than 60 seconds in this game.
Additionally, this gap in mobility makes the Vasari Exodus pretty much the categorically superior choice compared to Vasari Alliance, since they don't have to worry about this problem because of their ability to be completely independent of planets. Adding back an option for Vasari to quickly return home to friendly phase stabilized planets would go a long way in balancing the two subfactions against each other IMO.
My suggestion would be to bring back Stabilize Phase Space as a regular ability for the the Antorak, replacing the frankly not very useful Sabotage ability. I think this would bring back some much-needed defensive mobility for the Vasari, while not being overwhelmingly powerful due to it being temporary and available only on one type of capital ship. Or if having it be a regular ability is too overpowered, it could be brought back as a level 6 ultimate ability like it is in Sins 1. Or if the devs are feeling generous, maybe even as a ship/starbase item.
No matter which option is chosen though, I definitely think the Vasari need access to some sort of way to create a temporary phase stabilizer around gravity wells they don't own.