From what I hear, the entire Magic system has been changed up. So of course Power Focus won't stay the same. Things change and you can't let items stay the same if the mechanics they work with have changed themselves. Hacking has changed and will once more with 5e coming 'round the bend, ware has been changed quite a bit, damage changed and far more, not just the Power Focus. And if things have been tuned down, that's even more reason for the Power Focus as well to have a lessened effect, since it's already usable in the place of many Foci all in once.
If you think it should work the same as before, that's between you and your GM. But the rules are clearly written on this and Power Focus, like so many other things, has gone with the times. The way you'd like it to work likely would completely break the balance, so I can't say I'd disagree with a GM keeping things according to RAW.
That doesn't mean Mystic Adepts aren't doable, it just means you can't be as good as a magician and as good as an adept at the same time.
Just a side note, isn't a Force-6 Stunbolt still just 2P drain? Even at 9 resistance dice that's only 0.17P damage on average.