Always happy to read your contributions
Land has a clear advantage in the areas you list given that it is a hybrid with BAs and e-stats. I would make the same claims about Elysium over Isabellae (Ely wins in technicalities) and for the same reasons-- the drivers Elysium (and Land) use lend themselves to imaging, speed, note definition, airiness etc. in ways that a single DD cannot keep up with. A single DD does have its advantages though, if exploited through good tuning. These include primarily for me things like 1) single driver coherence, which gives the overall sound a fundamental unity that is, as a rule, easier to embrace emotionally (whereas technical skill is, by and large, more intellectual in character) and 2) the advantage of having natural DD timbre from top to bottom.
For me an IEM that, through great tuning, exploits the potential of a single DD to the fullest is the Oriolus Isabellae. While I consent that Elysium excels Isa in all the ways you list as Land besting Zen I cannot fail to note that Isabellae at its best presents no less an enjoyable listening experience as the Elysium-- and in the right circumstances even excels it in some ways.
I have been thinking a lot about this in light of some of the great discussion that has been taking place in this thread. I will address this further in a reply to
@SBranson below.
I think it's partly the e-stats. They have a capacity for speed, weight and clarity that is really special...especially the second gen of e-stats in Trailli, Spark, Odin (and I'm curious if they're in Land).
I think this is a huge part of it. The Isabellae has really opened my eyes to what is possible with summit fi tuning. Also, while I haven't heard the Zen I have heard that it has quite. an "Eastern" tuning to it-- which is consistent with your description of the mids. That and harmon tuning are two of my biggest turn offs in IEMs....not that people can't justifiably love them, I just don't.