I don't know how that would have been bringing Mystic Adepts down a peg at all, then. For the exact same priority array, you can either play an adept with 6 PPs, or an adept with 6PPs who can also conjure spirits, and post-chargen learn spells, to boot!
See, to me part of that last sentence is the key. 6e elected to treat the symptoms of the incorrect affliction rather than cure the disease. Ask yourself this question: "If spirits and foci were better balanced, how would each mage, adept, and mystic adept look in comparison to one another then?".
As things stand at current with spirit abuse aside (because we all know that is pretty much all you need to be a one man team), Mystic Adepts come out the door considerably inferior to either mage or adept. In the long term, they have the potential to be better than a mage at spellcasting and summoning (because mages cannot access improve ability), and better than an adept at physical defense (equal level combat sense as an even karma total adept, plus increase intuition which adepts cannot compensate for). Those are the only two areas where they have the potential to defeat the other magic archetypes in power though, and doing so is very intensive of their more limited resources. If you really need comparative builds at a respectable karma level I can do that to highlight.
Doing as I suggest would yield the following results at chargen:
1). Mage enters play with Magic 6 and 12 spells.
2). Adept enters play with Magic 6 and 6 PP.
3). "Balanced" Mystic Adept enters play with Magic 6, 3 PP, and 6 spells.
That is a relatively even playing field, with in which Mages and Adepts will have steady growth within their field, and the Mystic can either have steady growth in one and stunted in the other, or intermittent growth in both. At the extreme side of chargen, taking either all PP or all spells, you basically are just playing a Mage or Adept that can give up steady growth to splash into the other field.
In 5e this was a problem due to how many defensive spells there were. In 6th, as it stands now, it is far less of an issue.
If a MysAd can end up with as many power points as a PhysAd, but still conjure and post chargen learn spells, to boot? No, that's not "balance". That's where there's no reason to play a PhysAd.
On this we agree, but at no point in character advancement is that possible. An equally experienced Adept will always have more PP because they get them both on Magic increase and Initiation where the Mys can only get them through Priority and Initiation (or through Initiation post-chargen with the rules I'd prefer).
I think we should agree to disagree as to whether PhysAds being able to go to 6 PPs in chargen and Mysads capping out at 4, IF they pick Magic A, is a good balance or not. Arguing about it isn't going to change either opinion.
This is another really big deal though. With the (good imo) errata, Adepts are back to D magic priority and spending points to get Magic 6 and 6 PP. In order for the Mystic to potentially get 4 PP, they just gave up 8 attribute points. That is a fucking titanic sacrifice that is not remotely worth it karma cost wise.