There's no walking, it's very different outside of the combat. You're riding on your stagecoach towards a mountain which automatically moves at a steady pace, crossing multiple zones that are like the first game's dungeons, with inns in-between them for resting and purchases, and you fight a boss at the end, and then repeat it with increased difficulty and complexity, the more bosses you beat the longer the trip becomes, and new zones unlock. As you ride there's dozens of randomized encounters with all sorts of things from helpless people asking to be saved to enemies and shrines that play story segments and merchants and an oasis and so on.
The game is streamlined in that you don't really need to grind and you don't lose as much from dying, you always have every class available and if someone dies mid-run but you survive to the inn (not an easy task at all) you can fill their spot with someone else from the unrecruited classes, and those who survived a mountain boss get these memories that are passive buffs, significant ones, and if they die they lose those, but that's all, things like upgraded skills are done on a run-by-run basis as opposed to being things you build towards with your resources after adventuring, and there's no equipment or hero leveling either. Heroes just unlock more skills by you doing their shrine events, and skill unlocks are free and permanent, which is very easy to do, it just takes a while cause they have way more moves now, each one has like 11 moves now, and can have 5 active at a time. And trinkets again you just find as you are out on the field when you defeat enemies and run into merchants and so on. It's all very streamlined, there's just 1 resource you collect to power up which is these candles of hope, and everything else you just scrounge up as you're doing the adventure. Each run gives you just enough money to buy stuff with too.
As for the combat itself, they have de-emphasized healing and defensive tactics including stun a whole hell of a lot (healing skills require you to be under a certain % of health to become usable) so the old approach of stunlocking and constantly healing your team to max health to slowly defeat enemies is not valid any longer, but there's a ton more stuff in the combat to take its place too. I wouldn't say it's overall that much faster but it's more aggressive and complex by a whole lot.
Basically this game is not nearly as much about leveling your stuff as the first one was, and more about trial and error so you figure out how to defeat the enemies and what skills do and what skill combinations work and so on. It's like you're trapped in an endless nightmare while the world around you has gone to hell and you're trying to stay sane while keeping hope alive and confess your sins that somehow caused this situation. Each sin corresponding to a boss fight.