Mor Ephrem, could you tell what you find so beautiful in the Traditional Roman Liturgy? I love the whole "propers" thing in the Roman liturgy, but its action seem to me more like a spectacle than a liturgy and it's a great pity. For me it lacks also an obligatory choir, as in EO, giving the People a strong voice. And comparing with EO it seems to have very short Liturgy of the Catechumens. But I'm open to be convinced (for the "propers" sake ).
I haven't really thought this out systematically, so take these with a grain of salt.
Before anything else, I'm glad I don't have to explain the appeal of propers.
Honestly, I feel that the traditional Roman Liturgy flows better than the Byzantine Liturgy. I've worshiped with EO for years, am comfortable with the Liturgy in various languages, etc., but the Byzantine Liturgy seems, to me, like a bunch of "parts" put together haphazardly so that there is some semblance of "order" and "purpose", but you have to know what to look for. Based on the history of its development, I don't think that is an inaccurate assessment, even if it is very incomplete. In comparison, I think the Roman Liturgy clearly has an apparent "order" and "purpose", and flows seamlessly from one thing to the next.
Let's take the Liturgy of the Catechumens, since you brought it up. The Byzantine version is longer only for two reasons, IMO:
1) the Liturgy of the Catechumens includes everything from "Blessed is the Kingdom" to the Little Entrance, and
2) has not omitted the intercessions
Re: #1, the real "start" of the Liturgy is the Little Entrance, with its entrance chant ("Invitatory", if you will), processional chants roughly analogous to the Introit (e.g., apolytikia and Trisagion..."Only-Begotten Son" was also one of these at one point), and fairly quick progression into the readings. Seen in this way, the Byzantine Liturgy of Catechumens is roughly the same length as the Roman Liturgy of Catechumens. They have less sung material, but the settings are more complicated, while the East has more sung material but can be sung simply and more quickly than a Gradual. If you factor in all the material I included in #1, the Byzantine will definitely be longer.
Re: #2, the Roman Liturgy has dropped the prayers for the faithful offered after the Gospel (even while retaining the Dominus vobiscum-Oremus), while it has been preserved in that very place in the Byzantine Liturgy (among other places). ISTM the Kyrie is also the remnant of some litany-like structure, even if it has become a penitential prayer in the popular imagination.
So I don't think the Byzantine Liturgy is "longer" in this regard, as long as we're comparing the right sorts of things. Also, it depends on how "completely" or "incompletely" certain things are done. Roman Liturgy doesn't have that much flexibility.
I think the traditional Roman Liturgy can be served with too much "spectacle" (sometimes it looks like a military drill and not worship), but as Alpo has alluded, I think this can equally be said of the Byzantine Liturgy in some regions. This is especially true if we compare Pontifical Mass with Hierarchical Liturgy: Byzantine Liturgy is almost completely theatrical with the bishop being the star of the show, while the Roman Mass has managed to find a balance between a) performing the ceremonies emphasising the role of bishops which are natural to this form of Mass and b) allowing the bishop to eventually disappear enough to allow the worship of God.
Regarding choirs, perhaps it is different where you live. With very few exceptions, most EO parish Liturgies I've attended involve either a few chanters or a choir singing everything while the rest of "the people" are mute spectators. It's really no different from the average traditional Latin Mass parish. In both cases, when people want to sing, they'll sing loud and proud.
I don't know if any of that made sense to you, I think it's rather haphazard myself, but I just responded to your observations (I suppose I could go on if you pushed me in a particular direction, but this is all I've got for now). I don't think the Roman Liturgy is without its own issues, I think there are things I'd change or adapt, but overall, I think it "works" better than the Byzantine Liturgy. I still think Syriac Liturgy trumps both, because it seems to have found a way to embrace the best aspects of both without necessarily having been influenced in this way by either.