I'm hesitantly excited about the idea they are updating Limbus and old content for that matter. I agree with Saevel it makes the most sense for them to do (I think you pointed this out in the past also and specifically named Limbus?), it'd be interesting to see if they continue that concept beyond Besieged and Limbus in the coming years.
I do wonder how they plan on handling entry and queueing though. Older content can be a PITA to enter if it's a busy time and I wonder how much of their re-implementation is gonna be focused on fixing that vs actually updating the content. Asura problems. This is why I'd also expect a Sortie, not dyna, KI system instead of Omen-style, but I don't remember much about how Limbus worked in era either.
Was anyone that speaks Japanese able to translate the segment of the video where they talk about it? The YT subtitles are suck, but they briefly mentioned Relic/Artifact armor and some of the challenges associated with doing this, but not clearly enough for me to understand the context.
I've mentioned Limbus for awhile because it would be so easy to update due to how compatible it is and how it wouldn't need crazy new mechanics.
Entry queues would be the same as all other "instanced" content including existing 75 Limbus (seriously). You have an entry item, either a KI or actual item (cosmo clense) that is only available after X amount of time. You gather at either Temenos or Apollyon, party leader would interact with device and chose the tower, then everyone gets pulled into that tower, end of story. The only difference is that instead of having a single Western Temenos map (example), they would have four or five of them.
See the FFXI engine doesn't support real instancing, instead what we get is a single zone with copies of the battle fields. When groups go in, they get assigned the next available battle field, and when they exit that map gets reset for the next group. Sometimes these resets kinda glitch, which is how you can sometimes see an older boss when you zone in to Gaol. Limbus does something like this already, each "Tower" is a different map and acts like a separate "instance" from the others.
Maybe they'll throw a conflux inside the entrance or something akin to Selbina HTMB, because currently only 1 group per Limbus zone and that would be a disaster.
Already exists, it's the telepad where you select your tower.
So I have a level 75 alt I play around older content with, this includes limbus. Go out and do some of the zones just to see how it's already halfway to being properly instanced. They just need to ensure there are multiple copies of each tower.