The only reason I went with a sandbox instead of VN for this was because it allows me more freedom event-wise. In a PL like VN, I'd have to have Eve tell you to visit her tomorrow and then have 20 filler scenes to make the in game time progress enough to where it's tomorrow and you can finally visit Eve. Now I can just have a scene of Eve telling you that, and the next scene is you going to her tomorrow. This isn't necessarily a VN problem, just a "my kind of VN" problem.
I won't be adding any grind to this game whatsoever. There'll be random events and such in future versions and the TV in mc's apartment will have some cool interactions with it, but aside from that, the overworld won't serve much of a purpose.
Also event only mode sounds good, I might make that.