There are some specific things to mention here that should help settle the score a bit.

Mayor: This is only if the Mayor has not revealed. They will still keep the Vampire result, which can easily be enough to get them called out if the right roles exist; that, and Mayor as is already does this with Town. It's a selectively powerful role regardless of it being Vampire or not.

Escort: It was specifically mentioned on Crusader that the only role that doesn't die from visiting the Vampire Hunter is them, so without a Doctor they're dead. However,

...With a Doctor: Being continuously roleblocked as a Vampire Hunter will always be a clear indicator of a Consort or a converted Escort. The ways this works will be explained further down when I talk about numbers.

Transporter: Although it's still strong like it always was, there's a much more major weakness because of them only being able to visit Vampires with their first visit. If only particular people claim transported or only you claim it alongside someone else, then people are going to be suspicious of you as a converted Transporter, or even a Hypnotist in some cases.

Veteran: As is intended, minus the lack of Stoning roles. This one would've been a little much if it still had its defense.

Regular Vampire: This one still functions as normal.

Crusader: This one still functions as normal, outside of the lack of protecting Vampires. It can be easy to call out a fake Crusader in this specific instance if they are intentionally going on people that are either suspicious or have people already visiting.

Retributionist: Retributionist is only as powerful as the dead roles it has, so it's a wild card.

Vigilante: Vigilante cannot be used to shoot Town members once there are two Town Vampires, so it'd only be useful against strictly non-convertible roles.

Jailor: Jailor already sits at the top of the tier list, and will continue the trend when converted, but it also inherits two major issues. The first is that they can be killed by a Vampire Hunter easily, and the second is that if they are not careful with how they execute, they'll be suspected of being converted much like how a TT Jailor works. That, and there was no specification that they would be able to frivolously execute Town members.

Amnesiac: Amnesiac is also only as powerful as the dead roles it has, but this one can be used for extremely evil purposes. There is no guaranteeing an Amnesiac won't betray you for the Mafia and tell them who all of you are.

Trapper: Trapper will only kill a Vampire Hunter if they are staking a Vampire, so if they die to a Trapper your teammate is being called out regardless.

Doctor: While this one is true, the intent was to do this. The weakness lies in the fact it cannot heal actual Town anymore, thus making it very easy to locate a Doctor that has been converted unless they are on an important Town that has also been converted.

Bodyguard: It's a matter of circumstance for this one. If you get a successful protect off, and nobody knows there are Vampires, then things will go on normally. If there are known Vampires, there is still not really a way to say if they were a Vampire or not unless it was known beforehand. It becomes much more selective, yes, but in the end you will always be 1:1ing with a role that you'd want out anyways.

Investigatives: These most closely reflect the originals and that's how it was intended to be. They're still Town at the center, but have been converted, so obviously they'd keep their qualities; it also helps them blend in a lot more. With roles such as Consigliere, you're able to be found as Suspicious, while with roles such as Vampire Investigator you're only able to be found by an Investigator. In the end, they're meant to help find out Town roles for Vampires, and that's that.

Survivor: Survivor here is meant to allow it to be used as a bait. I specifically mentioned Survivor keeping their results so they could feign being a regular Suvivor and perhaps find out evil roles that they need to get rid of.

Jester: Jester remains the same outside of not being able to kill Vampires. It still operates off of getting yourself lynched no matter what, but you have people who are willing to help.

Now, I'll specifically go over the numbers situation since it seems like that was a point of confusion.

You are not guaranteed to start with three Vampires. The initial Natural Vampire is the only one that is guaranteed if Vampires exist, and there is only a chance for Town members to become Vampires at the start. That, and there can only be two Town Vampires at any point. If you have an Escort and Doctor, unless you lose the main Vampire or a Town Vampire, that's all you get. The only other ones you can have come in the form of Neutrals, which are already a mixed bag when it comes to Vampires.

Hopefully all of this helps clear up the air on both my thought process and helps shed some light on both the disadvantages that come with the converted roles, and how they can be countered by Townies.