Nah its not about the tutorial segments in general, but just how every character that joined Lyn in her small personal quest, had a piece to say every chapter or so, Kent & Sain most so, and I feel its part of why they remain my favorite cavalier duo in the franchise.
There was this sense of comradery, that Lyn's group had, from Wil finding the camp, and Kent making suggestions, Sain trying to hit on every girl but everyone joining in on the joking at his expense. Erk & Serra's squabbles, although admittedly Rath and Wallace didn't have much, but they didn't have much of a chance to be.
I guess its just something I always felt FE lacked since then, 7 was my introduction and I thought the entire game would be full of everyone just joining in randomly in the conversations, I guess with the Tactican on certain maps having say, Sain talk to you right before the start of Dragons Gate (if he was one of your units that map) was cool, but I noticed in pretty much every other FE this is not the case.
The casts being so large is mostly why I think they don't do that, and its unfortunate, because it added a-lot of likability to characters (Ike talking to everyone over the course of FE9 is the closest thing I can think to Lyn mode everyone pitching in). I can see why people would want a smaller cast, not only for balance purposes (potential loss of replay value) but also little things like this, so I was curious if anyone else felt the same about this.
Edit: How did I forget that FE12 also kinda did this lol