In the end I think the oneshot was better. I think it had far more impact in its short number of pages (also better art).
I think a big problem of the story is its pacing, nevermind the awful release schedule (of the OG work, 6 months for a chapter? Jeez). Kagis spent too much time setting them up to get together again only to show how they are essentially at completely different stages of their lives. Maybe it could have helped if they had been more intimate moments before the big fight and miscommunication. The weird domestic violence felt really at odd too with the work.
Also I find the idea Issei stayed a virgin (and possibly in the closet?) all these years so silly it almost took me out of the experience and a weird change from the oneshot. Like some weird purity change the story really didn't need (When what made the OG oneshot cool was how irriverent he was about it).
I'd say, there is a certain appeal to the story in how imperfect it is, sorta like taking a peak at some dude's everyday. Nacchan's problems and hard to fix and relable. I think Kagis is at least good at giving their manga "down to earth" vibes.