Well travel time on XI was "ok" at first, when you discover the game, enjoy the Airhsip music, discover that monsters can spawn, get killed on the Airship and raised by someone etc. But after a while ? All people were doing was AFK'ing until the ship gets there, then AFK more during travel.
That's surely immersive...
I don't see the issue with instances as well... XI had tons, never been an issue. Would you call Salvage, xNMs, Assault, Nyzul not immersive just because they were instanced? What about private (not technically instanced, still reserved) areas like Dynamis, Limbus where there was only people you know in? We all did this, no one complained that it made the game "less immersive" because instanced.