Roon Nucleus vs Innuos

I haven't compared the units you are referring to.  My response is based on similar components. 

Separating Roon Core from Roon Endpoint/Renderer is important and delivers clear performance upsides.

They can be combined but to do so well (as in high performance well) is costly and not easy.

If you are going to try Innuos (I'm not sure which model level), I'd keep the Nucleus to see if using the Nucleus as Roon Core feeding the Innuos as Roon Endpoint is superior to Innuos on it's own. If the Innuos better suits you it will be easy to resell the Nucleus.

In any case, would love to hear your findings whichever path you choose.

Innuos can be used as Roon Core, Roon Endpoint (Player), or Roon Core + Roon Endpoint (Player).

there is really no empirical evidence that separating a Roon Core and Endpoint are actually better

There is a ton of user feedback on separation of the two functions yielding better overall performance. One can head over to Audiophile Style (formerly Computer Audiophile) to learn about this.

I have taken and tested this approach. Isolating and separating the functionality clearly has been superior in my applications. N of 1.

NOTE: I’m not saying this is or isn’t the case with Innuos. Nor did I say so in my above post.

For example, Antipodes (a Server/Player company) has found this to be true (for them) and has taken the approach of optimizing Server/Core and Renderer/Endpoint/Player capacities SEPARATELY as their BEST OPTION.

As always, there are many approaches to achieving performance, with different companies taking different paths.

adds the variable of the sending data over the network.

I agree. However there are solutions to allow for the elimination of a Network Switch (if this is what is being referred to). The data has to be delivered over the network, no matter what.