Is Heightened(4th) Silence spell balanced?

Question

The second level spell Silence can be heightened to 4th level, when its description is as follows:

Heightened (4th) The spell effect emanates from the touched creature, silencing all sound in or passing through a 10- foot radius and preventing any auditory and sonic effects in the affected area. While within the radius, creatures are subject to the same effects as the target. Depending upon the position of the effect, a creature might notice the lack of sound reaching it (blocking off the noise coming from a party, for example).

This means that without any saving throw any caster that is near the target is utterly defenseless against physical attacks and unable to do any meaningful action, and this is regardless of his level.

This is because most spells have of course a verbal trait.

Just by this threat existing any wise magic user must take into account that he must have some kind of strategy to avoid such a situation and this is a very deep rabbit hole.

What I want to know is if this is taken into account in the balance of the game or if this is something that has somehow slipped in and we really should let any caster at least try to avoid the effect by adding a saving throw every turn they are inside the silence area?

Answer 1

It is balanced

Usually it just means the caster needs to Stride 2 squares. Most enemies do not have Attack of Opportunity, so you can safely do it, and even if they do have it, it is just some damage, cannot disrupt the movement.

You are in more trouble if you are Grabbed and Silenced, but then you can just try to get out of the Grab, most casters tend to do that anyway even without Silence, as Grab imposes a flat check on Manipulate.
I think the reason why the 2nd level version does not shut down spellcasting is exactly Grabs, more specifically that Freedom of Movement is only available as a 4th level spell.

And of course you have other party members, who should be able to help, by moving you, the enemy (thus ending the Grab), or casting Dispell Magic.

Just because you cannot easily do what you usually do, it can still be balanced.
Think about Golems, they are immune to magic, should blasters get a saving throw?

Answer 2

Yes, based on other 4th level spells

4th level spells give you options that:

• let you fly, negating any ground-based dangers and melee bound creatures
• Stupefy spllcasters, giving them a spell failure chance that (almost) cannot be mitigated
• Dazzle martials, giving them a Strike miss chance with very limited mitigation
• Render large swaths of battlefield dangerous to walk through or simply inaccessible

And that's just Common spells that begin with a-c (specifically aerial form/air walk, anathematic reprisal, chromatic armor, and coral eruption). Silence might force an enemy to make suboptimal choices if they are forced into... and it should, as a 4th level spell that lasts (probably) one conflict.

In a lot of ways, many level 4 spells are very specialized at shutting something specific down. Freedom of movement is the bane of creatures that need to grapple. Globe of invulnerability shuts down low level spellcasting. Enervation murders anything that is living. Ok, that one's less situational but I think you see what I'm getting at. A small area, even mobile, of "can't use verbal components or audible traits" is fairly on-par.