VL titan is by far the most powerful titan in game...it is the only titan that can tackle corvettes pre-lvl 6, and when it does get to level 6, it's getting a much better ability than dissever....
Even if desperation didn't affect corvettes, desperation is still going to outperform the other titan AoEs, in no small part because of micro phase jump....hell, I'd still take the VL titan over the other 5 even if it didn't have an ultimate ability....the supreme raw firepower of the Vorastra is just a nice added bonus...
The only broken thing about VL is their titan...it is the hardest to kill and the most devastating against enemy fleets....you can't easily corner it, and you can't easily run away...
VR on the other hand are ridiculously broken...
First is their titan...while not as good as the VL titan, the Kultorask is clearly next in line at low levels....it is much harder to brute force early/mid game than the Eradica and isn't as vulnerable to PMs...
Second is jumping starbases...this is obviously broken, no need to further discuss...
But there are other factors as well....for one, PMs are already practically broken in Vasari vs. Advent matchups, mainly because of the unusually high base damage of Vasari bombers...that VR get stronger PMs just completely breaks any PM wielding units....then we have the fact that they can let allies use their phase network, which means that the other factions (who are specifically balanced around NOT having phase nodes) now get one of the most powerful abilities in the game....
Too many people like Vasari for what they are, OP or not, and if both races were banned you'd have a lot of pissy people....the only thing wrong with VL for the most part is their titan...PMs and Orky rushes are annoying and arguably problematic, but it's really the titan that sets them over the edge....but, an OP titan is I think easier to deal with than OP EVERYTHING that the VR have....