I suggest that lyrics be linked to compositions rather than albums. That way, lyrics are available to all identified cover songs.
Which is a no go for timed lyrics (a.k.a. Karaoke Style) as they only work for a specific performance.
And then there are all the composition that exist with different (e.g. foreign language) lyrics. So the user must then select manually which lyric variant he wants to see?
Some kind of a “Libretto Feature” tied to compositions - in addition to lyrics tied to recordings - would be far better I think. Problem is there’s no reliable sourcing available for a thing like this. 
I certainly understand the timed lyrics, but you lost me on foreign languages. Why not just display the same lyrics across all performances, as per the user’s preference?
So, it remains a definite go IMO.
Where/when should the user set this preference? What to choose from?
E.g.: Like this 
for the lyrics?
If someone sets the preference to German and then listens to a composition - the actual performance is in french - for which Roon has english and french lyrics in the database, which lyrics should Roon present? Why should Roon present the english lyrics for the french performance or vice versa?
Please keep in mind that other language lyrics aren’t just literal translations of the original lyrics. They most often have to differ to match up with the composition. They can even have complete other general theme / meaning than the original. Doesn’t always has to bee so extreme like this one:
And the purpose of another meaning or parody is not limited to translations only.
That’s why I think that a “one fits all” solution is not desirable.
A frightening example. 
Some stuff is better forgotten than mentioned in encyclopedias …
Yeah, it is pretty much an impossible feature to enable. Never mind.
While this would be nice, it would also require a way to override the composition lyrics with track lyrics. In non -classical genres, cover versions or re-recordings of the same composition by its original artist don’t necessarily use the exact same lyrics. Cover versions may also be in a different language