Yeah I'm working on my review this weekend (been busy) and I agree with Haruka part but damn did I feel like they did a splendid job with this one. I think you should replay Yakuza 1/2 because I felt like they also had pacing issues. The issue with the multiple characters is that you get to a height of a story then have to RESTART a start for a new character and one of the issues that Yakuza team has is they grind the start of a story rather slowly but when the pieces start clicking I'm like "Damn."
I know what you mean about the occasional pacing issues in Yakuza's 1 and 2 but I found them to be more occasional than the ones in 3, 4, and 5.
I re-played through Yakuza 1 actually right after beating Yakuza 4 and while there were occasional filler missions, there were none such as throwing 1 character into a prison yard and then onto an isolated mountain for hours on end with no connection to the rest of the story just as the story was picking up steam.
With 1 and 2 I remember it being more like the occasional collect-a-thon fetch quest, or something like that. It felt like Yakuza's 1 and 2 were more afraid to interrupt their storylines, where 3 (and especially 4 and 5) I guess partially due to 4/5's multiple character structure, they didn't seem to care as much.
I dug Yakuza 5. With the exception of its soundtrack (which was leagues behind Yakuza 4's,) I think it's a better game than the past couple installments and definitely a worthy entry. I'll have more of my thoughts in my review. There are areas in which I REALLLLLLY wish this series would move forward, but I still have a blast playing them and am stoked to continue playing future installments.