Nothing happens in the first seven chapters.
This game didn't need to be a trilogy.
It needed to be a properly told and paced story.
Really, there was a lot that could be filled in. If open world wasn't a thing, and the team wasn't constantly streamlining the same giant cake of land to get it up to acceptable visuals and performance, all that effort could have gone into making small instanced chunks of gameplay - not necessarily linear, just instanced, like FFXII (and - look at the dungeons - aside from wonky camera the level design is really, REALLY good in these small chunks), with each rest stop or outpost being significant to the story as you get to them in order rather than stumbling upon them serendipitously, sidequest chains also likewise being more integrated into the overall plot since you'd be able to have a rough idea of when the player comes across them instead of again becoming serendipitous, there's really a lot more you can do with the story.
If, say, Lucis had been divided up into 3 continents separated by water rather than 3 baked-together regions, with a bridge or boat connecting both, and you had a clear sense of progression going from one to the next, it'd be easier to write in a longer narrative, since you'd have plots of land that the player is going to traverse in order. As it is the entire continent had a bunch of gates to limit progression but it was still pretty non-linear as of Ch3.
If you ignore any preconceptions for versus, from an objective standpoint I don't think there's a lack of
towns perse. There's Lestallum and Altissia which are the big ones, then Old Lestallum, a couple of rest areas, the gas stations, Wiz Chocobo Post, Caem, etc. I'd argue that in terms of scope, they're similar to the smaller JRPG towns in that they have an inn, shops, and some extra flavor buildings you can't enter just because, and some treasure to find. However, they do lack in differentiation and meaningful denizens/questlines which again goes back to the whole open world design aspect.
I think this really was a learning experience for Square Enix (or, at least BD2) in how to create, design and most importantly execute an open world. I think the same team taking on FFXV with the knowledge they had now, given another 4 years (2012 to 2016) would be able to create a much better product. In the end, this really is the first western-style open world they've put together, while also creating a lot of the tools and tech along the way, and quite likely the first time they've taken outsourcing to such a high degree.
All that being said, I really, really like FFXV for what it represents - pushing the envelope in some significant ways. I think it sold the premise of a road trip and of brotherhood remarkably, even if everything else took a big hit. It's also technically very impressive and the visuals are probably going to scale well into the future.
I don't think I'd want every Final Fantasy to be developed this way (heck, I don't think BD2 wants to either what with the crunch at the end) but I enjoyed it thoroughly for being different.
Prompto deserved to live.