Is this buff to the Clairvoyance spell still the power of a 3rd-level spell?

Question

I want to give Clairvoyance a buff, as it is a 3rd-level spell that is a little bit underpowered in my opinion.

Here is the current text of the Clairvoyance spell (from D&D Beyond):

You create an invisible sensor within range in a location familiar to you (a place you have visited or seen before) or in an obvious location that is unfamiliar to you (such as behind a door, around a corner, or in a grove of trees). The sensor remains in place for the duration, and it can't be attacked or otherwise interacted with.

When you cast the spell, you choose seeing or hearing. You can use the chosen sense through the sensor as if you were in its space. As your action, you can switch between seeing and hearing.

A creature that can see the sensor (such as a creature benefiting from see invisibility or truesight) sees a luminous, intangible orb about the size of your fist.

And I would like to add the following:

While seeing or hearing through the sensor, the sensor has a move speed of 10 feet in any direction. It cannot take actions (including the Dash action), it cannot move through objects (even as thin as a piece of paper), and cannot interact with its surroundings (i.e., it cannot open doors or windows). If the sensor is moving and something larger than 1 inch collides with it, the spell ends.

Would this change maintain Clairvoyance's 3rd-level ranking? Or would it bump it up to a 4th-level spell?

Answer 1

It would bump the spell to 4th level

By adding movement speed to the sensor you are making it quite similar to Arcane Eye, which is 4th level. Comparison of your version of Clairvoyance with Arcane Eye looks like this:

Advantages over Arcane Eye:

• MUCH larger range (1 mile vs 30 feet)
• Ability to switch between visual and audio data

Disadvantages over Arcane Eye:

• Three times slower movement (10 feet vs 30 feet)
• Shorter duration (10 minutes max vs 1h max)
• Requires components worth 100gp
• Doesn’t provide Darkvision unless the character has it already
• Larger - the Eye can fit through 1 inch opening whereas the sensor cannot, probably also easier for creatures to notice it for the same reason
• Slower to cast (10 minutes vs 1 action)

Also note that moving Arcane Eye explicitly requires an Action whereas you haven’t stated this in you spell version, I have assumed the movement works in the same way for both but if not, this could be another advantage for your version of Clairvoyance.

All those are quite situational and will only make a difference in specific circumstances, I don’t think adding this movement speed to the spell makes it better than Arcane Eye but it definitely makes it comparable, therefore I would bump it to 4th level but no higher.

The closest 5th level spell you can compare this to is Scrying, it can also be used to target a location and it is noticeably better as does not have a distance limit, only requires that you know the location. Therefore I would not bump it as high as 5th level.

Answer 2

This is comparable to Arcane Eye

I don't think it is strictly better, because the eye can move with a speed of 30 feet, and has a duration of an hour, so you can explore a much larger area with it, and that is how it is often used. With an hour you can scout an entire open cave system or castle. If you move the eye every round of its duration, you can get to a maximum range of about 3.4 miles.

With 10 minutes and a third of the speed, your new Clairvoyance is much more restricted. But in return it has audio, and can be cast behind closed doors, while you need a path of access for arcane eye.

Arcane Eye is fourth level, so I would put this at fourth level, too.

At fifth level you get to Scrying, which has no distance limitation at all anymore, allows you to spy on someone even if you do not know where they are, and can follow them no matter how fast they are moving.