The Velvet Room is a crucial part of the Persona franchise. Without the services of Igor and the Velvet Room's attendants, Persona protagonists wouldn't be able to fuse the large arsenal of powerful Personas that they need to complete their respective missions. Therefore, Igor's abode will surely return in Persona 6; it's mostly a matter of Atlus deciding what form it'll take this time. It's already been everything from a limousine interior in Persona 4 to a prison panopticon in Persona 5, so the sky is the limit for the Persona 6 incarnation of the Velvet Room. Considering its track record, Atlus will doubtless come up with a creative way to redesign this recurring heart of the Persona world.
If the Velvet Room does return, however, it shouldn't settle for its usual role in a Persona story. Persona protagonists usually keep their journeys to the Velvet Room secret from other characters, which can be a little inconvenient and confusing for Persona narratives. Persona 6 should consider breaking that convention by inviting every Persona user to the Velvet Room, rather than making it exclusive to the protagonist. Not only would Persona 6's story benefit from a public-facing Velvet Room, but there's some major mechanical potential to explore by bringing more characters there.
Persona and the Velvet Room's Inconvenience
As a general rule, a Persona protagonist meets Igor and the Velvet Room very early on in the game, oftentimes well before they learn anything about the world of Personas and Shadows. Igor provides valuable Persona fusion services to the protagonist, while his various attendants keep records of the protagonist's past Personas and help them resummon past Personas. Although these services are clearly tied into every Persona game's plot, the Velvet Room is generally kept a secret. The protagonist's friends never learn about Igor's services, even though they're crucial to the Persona users' success.
This results in some pretty awkward and confusing scenes where the protagonist skirts around the truth of the Velvet Room. For instance, in Persona 4, the Velvet Room attendant Marie serves as a Social Link who explores the human world and meets the protagonist's Persona user friends, but for some reason, nobody asks or tells where Marie is from. In Persona 5, the Phantom Thieves frequently acknowledge Joker standing around doing nothing when he's called to visit the Velvet Room, and yet they never really ask what he's doing or question where his new Personas come from. It's clear that the Velvet Room's effects are visible, but they're never addressed.
The elephant-in-the-room treatment of the Velvet Room becomes even more confusing when considering the ending of Persona 5 and the third semester in Persona 5 Royal. During these events, the Phantom Thieves not only visit the Velvet Room in person, but they interact with Igor and Lavenza multiple times. Since none of this seems to distress Igor or Lavenza, there doesn't seem to be any actual reason that Persona protagonists don't talk about the Velvet Room. If the Velvet Room is only a secret because nobody bothers to address it, then maybe it shouldn't be a secret at all in Persona 6.
Persona 6 Could Revamp the Velvet Room
There are tons of benefits to letting the Persona 6 protagonist's allies visit the Velvet Room. For one thing, it'd simply be an interesting narrative development. Igor doesn't change much from game to game, but after the events of Persona 5, he might have learned a lesson. Igor may decide that the Velvet Room isn't safe from potential usurpers like Yaldabaoth, and so he opens its doors to other Persona users, helping more of them reach their full potential in exchange for greater influence and safety for the Velvet Room.
Mechanically, visiting the Velvet Room with friends could be interesting too. If Persona 6 opens up the Velvet Room, it'd naturally still offer its normal services of Persona fusion and documentation. However, it could also offer new menus that let the player adjust or customize their teammates' Personas. For example, with the help of Igor or a Velvet Room attendant, maybe players could use certain Skill Cards on a teammate's Persona for once, modifying and optimizing each team member's playstyle.
Alternatively, visiting the Velvet Room with a friend could be a great Confidant activity in Persona 6. A player could invite a friend to train in the Velvet Room as a way to earn points with them as a Confidant. Training this way could result in that Confidant's Persona gaining a couple of extra points in a stat or learning a new skill. It wouldn't be too different from Persona 5 Royal's jazz club, which offered the same services every evening. These mechanics would be a big change in Velvet Room tradition, but Igor's broad knowledge of Personas goes so far as to help the protagonist grow more powerful. Why not apply that knowledge to some more characters?
Persona 6 Needs to Defy Tradition
It's certainly hard to imagine such a public Velvet Room after years of secrecy, but then, such a drastic change is exactly what Persona 6 needs. It wants to be a bigger success than Persona 5, and Persona 5 is partially so successful because it revolutionized the Persona series in a ton of ways: vastly more detailed combat, ability-rich Confidants replacing Social Links, and much more. As revolutionary as Persona 5 was, though, there's still a ton of Persona traditions that it left untouched, giving Persona 6 room to innovate.
Not every Persona convention needs to change, of course, but the muddy secrecy of the Velvet Room should. Beyond Igor and his attendants' mysterious nature as supernatural beings from the Shadow world, there's not much justification for the Velvet Room being hidden from most Persona users. Persona 6 could seize onto that convention and flip it on its head, making the Velvet Room more accessible than ever. Growth is the name of the game in Persona 6, and the Velvet Room is prime real estate for growth. Atlus says it's working on Persona 6, so hopefully, it's discussing dramatic but positive changes like these as it plans the next big step in the Persona franchise.
Persona 6 is in development.