I feel that with the magic specializations especially, they are pretty handicapped compared to other comparable classes.
If you take your spells at levels 4, 8, 12, ect that leaves you with extra talents at levels 2,6,10
This means that you functionally get 3 cool things during PFS play.
3 cool things is a lot worse than the other options that you could get.
Arcane Example:
EX: Bard vs Warlock (if you still care about the social)
OR Magus vs Warlock (if you're more combat oriented)
Bard just gets his spells and can use them in any form. Bard has mind affecting abilities, can buff the party AND has a bunch of skill points with 3/4 BAB.
By comparison, the Vigilante gets some social powers and 3 abilities that are a little better than feats.
Your best options are:
1. Concealed Casting - if I had a dime for every time I got into the 'I cast suggestion' and the GM says, 'Combat Begins, roll initiative', I would be rich. This makes it hard to argue that. I think it would be good to have a reminder of what happens when someone casts a save spell on a target from no known source - Does the target know? What does the target know? But this is a good power. It's a shame the save DC of your powers will be low.
2. Educated Defense - This is a pretty cool thing.
3. Bombs - even with less bombs per day and having to splash a level of Alchemist to get INTMOD damage, this is still a good option.
I think there needs to be a lot more on the table to justify giving up on 9 levels of spellcasting for 6 levels and 3/4 BAB. Bards beat you in the combat game by a fair margin.
Divine / Zealot Example:
Just look at a Knowledge Oracle. It's got 9 levels of magic to do whatever you wanted to do, only better.
A more linear example would be the Inquisitor - they get Domains, only they don't have to pay class resources for them. And they also have some social standing. And they have Judgements. And prolific archetypes doing whatever you wanted to do.
Let's exclude Life Bond from the discussion, since it has some potential - you could give every zealot talent for free to this class and it would be worse than an inquisitor in combat by a fair margin (Although, obviously you couldn't front load it or people would splash the class).
Last, this class's casting specializations are falling into a 3/4 BAB trap with the Arcane and Divine casters. If you're playing a spellcaster, you need INT or CHR because you cast your spells with it. You can sac the other, but will be bad at one of the better things about the class - the skill list.
If you're intending to physically interact with monsters, you will have to invest in physical stats which will make you MAD and you will need to dump something to be effective - which will most likely be INT, CHA, or WIS. Even with high STR, you have no inbuilt to-hit buffs, and you have 3/4 BAB with 6 levels of spellcasting as your only way to buff.
If you decide not to participate in smashing face with weapons, your DCs will be low like Bards. You don't get the raw number of spells to buff yourself heavily like an Oracle or Cleric would. You don't have the Inquisitor or Warpriest's side abilities to help with combat.
Since you don't get to hit abilities, you're either going to be unable to hit / deal damage in combat without buffing. When you buff, you'll end up where many classes start out which makes the 3/4 BAB pretty worthless. Which then forces you to play the buff / support game / save or die bot, which you do worse than other classes
You CAN be a very skilled character, but the issue with this is that while you can do 12 (6+INTMOD + hat + human) skills with INT as a primary stat, it's reasonable for another class to have around 8 (2+INTMOD + hat + human) and the other class may also be effective at those 8, which doesn't give you very much of a niche.
