Thanks for the input, I appreciate it. This post is a reply to the points raised in UberFazz' post. I'll reply to the most recent two later.
Changing resolutions can cause differences in gameplay between users
If you mean resolutions that are taller than they are wide, I wrote about this in reply to Naxess. Could you explain why you disagree there?
If you mean differing horizontal resolutions, such as 16:9 versus 4:3, the proposal is limited to objects that are off-screen on the top/bottom side for this reason. For more about this, see my reply to DCT at the top.
The change would create a division between maps ranked before and after the change. the "gameplay area" would quite literally expand
Outside maps that center design at least in part on reading, there aren't reasons to use partially off-screen objects. Seeing as most maps don't focus on reading beyond trying to be easy to read, it's unclear how this would create a huge divide between past and future maps. Mappers aren't going to be pushing objects off-screen just to have a bit more space to map with at the expense of creating unnecessary reading changes, if that's what you mean.
This could very well mess with people's setups and how they're used to playing the game (for example, my tablet area is only defined in the play area, making off-screen objects literally unhittable)
I'm guessing that this will be seen as the most important argument, and it's also a bit complex, so I've given more writing space to it.
Noting the playing grid is a 4:3 rectangle (not a square), this is true for the top/bottom sides of the screen on a subset of tablet setups (I would guess a pretty small subset; I don't recall seeing any complaints about this around monstrata's aspire entry back it was being highly played). That said, there are fast and simple temporary settings changes that such players could enable to get around this, should they want to play one of these maps. For example, slightly decreasing osu's resolution until the map is done would work. There's also some possible changes to one's tablet settings which wouldn't mess with their aiming muscle memory; it depends on the specific player's set-up.
Another thing to consider is that at the end of the day, players do base their setups around the maps they play. If a player really likes these maps and wants to play them frequently, and if they're one of the subset who can't reach the screen's top/bottom edge with their current setup, they may choose to modify their default setup to let them play these maps without temporary changes.
This is also true for players who are still experimenting with different set-ups and haven't settled on one to use for a longer time. For these players, it's easy to notice that some maps have elements that are hard because of their set-up and to adjust their set-up accordingly without giving it a second thought. For example, many mouse players do this at some point early in the game when they notice they have cursor acceleration on, or that their DPI is set really high, and notice it's making it hard to aim. I believe players typically experiment a lot with different set-ups when they get a tablet as well.
All things considered, while it would make playing these maps involve a minor inconvenience for a minority of current players, I think the proposal would still improve the game overall by giving mappers a bit more creative space to work with, and by allowing ranked section maps to better fulfill the preferences of a broader amount of players and mappers
feels "gamebreaking" for the aforementioned reason - looks like a bug more than a feature
I understand why partially off-screen objects may seem like a design oversight on the surface level. I discussed this with another user earlier today, before this was posted, and brought up how arguably this was true too of the old controversies over maps not focusing on visual appearance. It was true in the sense that this seemed wrong to some players at first, but they came to understand it was a) intentional, b) something others liked, and c) an application of game design philosophies in mapping. The osu playerbase is efficient at communicating with each other and reaching an understanding on things that, to some, seem certainly off at first, and they should be able to clear up any confusion that some players could have.