the mobile sb is ment compensate for the lack of any other anti structure ship.
Yet as i mentioned before, the vasari new capital ship allows both a vasari starbase to gain more armor (which is arguably better then having carrier healing support), and it allows a player to build cheap, free building destruction ships. Considering that this new vasari capital is actually quite powerful, there is an incentive to spam it. Getting the healing and structure destruction capabilities early allow the vasari some early punch against structures without risking kanraks (this is huge). Endgame, the vasari have always used their BOMBERS to deal the bid punches anyways, so any talk about poor little anti structure ships is almost irrelevant, unless you talk of the TEC.
As it stands the advent's starfish still isn't that good, and still costs too much in logistics. This anti structure ship didn't get much of a recent change, its too limited STILL...
Also, the vasari have always had another good anti building technique, building the space egg to put a DoT and an armor reduction on a target, ensuring that even buildings go down with speed.
Its not like the vasari don't have serious options, its just that the vasari players want to limit the fun of the players that play other races. This has been the case as a long time player of sins of a solar empire for a long ass time.
The longer you new guys and gals play this game, the more you will see how the developers pander to the vasari, give simple ideas to the TEC, and still don't really know what to do with the advent. Its like they are programmers, who have a bitch race (TEC), a woman race that they don't understand (Advent), and a cool group of outcasts that they want to OP because they themselves are social outcasts (Vasari).
I find this very funny (and its not meant to be personal, programmer types) that the stereotypical view of the programmer is actually represented in the game design, if interpreted in this fashion.
the fully upgraded vasari starbase is a mobile slow moving AOE of death that doesn't have up front punch, but over time makes other AoE's look like childs play.
I don't see how mobile starbases would fix anything.
Have you ever had a human vasari player build a surprise starbase while your fleet is out engaging their main fleet?
Imagine how a mobile starbase, no matter how slow, would be able to engage that irksome vasari starbase before it is built, so that your already constructed starbase would then have an advantage over an alien construction project in your own gravity well? The current game mechanics of the game are only this rediculous because the developers pander to the vasari race.
The starbase being able to engage that vasari starbase while it builds ensures that this cheap and LAME tactic is only achievable when you have superior fleet. It doesn't weaken the vasari player's ability to A, have a strong starbase, and B, have a strong anti structure ship. The vasari would need to have a strong fleet to ensure that they can protect their starbase while it builds. Now this is reasonable!
also if you don't defend your gravity well with a starbase, you too would fall prey to this strong vasari combo. It shouldn't be a "one tactic fits all situations" strategy though. Having it this way simplifies vasari strategy to the point that really skill isn't that important, its the strengths of the faction.