Display multiple metric on tree map

[angorayc]

Current multiple metric on tree map is not rendering as expected:

Expected

After putting everything together, ideally it'll look like this (and legend sticks to Group By fields)

[elasticmachine]

Pinging @elastic/kibana-visualizations @elastic/kibana-visualizations-external (Team:Visualizations)

[markov00]

As stated in a call, I don't believe this is a good practice.
If I'm showing multiple values on a treemap I can face the following problem:

• is not clear what number refers to the size of the treemap
• it is useful for simple tree map, but if the treemap is complex, with a lot of nodes and with longer text, the text size becomes an issue and will vanish the effect of having a second metric

We can probably suggest to use 2 separate treemap, like a small multiple, one with one metric and the other with the rest. Reusing the same colors and connecting the interaction on both charts could increase the understanding of the value and improves the visibility of data.
cc @gvnmagni if you have other ideas here

[gvnmagni]

I find the issue very interesting but I have to say that I largely agree with Marco. It would be very complex for a user to identify what the numbers stand for.

It would be interesting to evaluate if there is a way to clearly inform the user about the role and meaning of those numbers, something so clear visually that it can't be misunderstood, but this is easier said that done and it should come with a solid re-design of typographic hierarchy within blocks. (attaching a very rough example)

[ninoslavmiskovic]

We have a similar ask from O11y to add metrics in the tooltip, so perhaps we can use that for inspiration or handle the JTBD. #106024