This is going to be a mix of different thoughts, concerns and questions. Todays devstream was a bit vague about how certain things would be affected, and while a workshop post with more details was teased, it's not out yet, so I'm including questions as something to consider addressing within the workshop, unless you're planning to do a broader QA kind of thing.
So, first of all: I am a little concerned about Grace - specifically, whether its intended emphasis of stealth is going to mean that you're just going to be stuck with inferior armour and no advantages as soon as the game throws you into an encounter that doesn't let you choose your own angle of approach, for instance basically every last bossfight, especially ones like Bromius, which throw you straight into combat. If I can't use stealth, in a fight, what does Grace give me? Courage, from what I understand will scale the defenses of the strongest armour, Spirit will allow me to make more use of my spells, what does Grace do once stealth is broken?
Second: Since I won't be able to change the attunement of weapons anymore with blessed joineries, doesn't that just mean that some weapons are going to be stuck scaling with a stat that doesn't even compliment their playstyle? Like, if Courage is what you need if you want melee survivability, what's the point in a big unga-bunga greatsword like the Needleseye scaling off Grace instead?
Third: How is this going to affect early game flexibility? Shifting around a few points is easy enough to make sense of early on, but this change means that if you want to try another playstyle, you'll require another prism item. How's that going to work out? At the very least, the basic starter prisms should probably be available from the faction ships right from the get-go for a low price.