There are some interesting, but distressing, explanations for the excessive height, remoteness and density of the iconostas, and we have been asked to address one of them in particular.
For a long time, I was opposed to "minimalist" iconostatses, but also uncomfortable with the remoteness, density and sometimes "darkness" of many of them. Also disturbing to me has been the meaningless opening and closing of the royal doors [gates] and the curtain during the Divine Liturgy (except for the Pre-sanctified, where it does have a meaning). In fact, I have come to appreciate the more "minimalist" iconostatses, so long as the concept of the separated altar as a type of paradise, and the ability to open and close the royal doors, as part of that revelation, is maintained.
The particular explanation for the denseness and closing of doors and curtains during the Divine Liturgy that we want to discuss is this: Someone asked an Elder why the iconostas was so remote from the faithful, and so dense, and why the doors were closed for much of the Liturgy. The Elder replied that it was because the first century Christians were much more holy that later Christians, so they could be closer to the holy things. As Christians became less holy, they had to stand further away from the holy things, and the holy things had to be made more remote from them.
Such an answer is completely unconvincing, particularly when one reads Apostle Paul's epistles to the Corinthians. What is more likely is that over-embellishment of the iconostatsis ran away with various architects. The height of many iconostases just became more and more exaggerated over time as one tier was added to another. The Solea and Amvon were heightened in part so that the Liturgy, the readings and the sermon could be heard by everyone in the church in an era before microphones and speakers. The reading of the Epistle and Gospel would have been heard only by those near the front of the church if they were read at "floor level." This elevation, which served a perfectly practical purpose did make the altar appear more remote from the people, but this appears to have had a practical reason rather than a spiritual one. It is obviously not necessary in our own era to have the solea so high that a proper Great Entrance cannot be made. The solea and altar area are not "stages" but focusses of the Liturgy, and it is the focus of the congregation that should be brought into the meaning of the Liturgy.
One might also suspect that the loss of the role of the laity (as a "royal priesthood") in the Liturgy has had something to do with the "remoteness" and closedness of the iconostas and the altar. Over the past few years, I have come to appreciate the restoration of single-tier iconostases (something that the followers of Abba Justin in Serbia have advocated), and ones that are more open to the congregation. My appreciation of the moderately "minimalist" iconostases has only been increased by hearing some of the explanations for the dense and remote forms.