I agree that more complex reminders with the features you describe would be quite cool, for both code reviews and birthdays would be cool, but you admit that the business case isn't quite there yet. (There is a glut of reminder apps on the app store, those features probably exist between all of them.)
Better sync software falls under the category of development tools; even Visual Studio is free these days (in the form of VS Code) because selling to developers is notoriously difficult to sell software to, because they know how to code. (There is also no shortage of open source inotify+rsync based sync tools.)
Fwiw, it's also a lot easier to hate on every idea than to believe in it :-D. I'm the first to be pessimistic, but I learned that you have to try something & iterate on it even if all you can do is find fault with every idea.
These were also ideas I came up with in like 5 mins. Just showing that ideas are a dime a dozen and it takes exploration to actually find something that works.
Here are a couple of ideas from my day-to-day as a programmer:
- Code review reminder tool. Code reviews are great but there can be social friction to getting them done. I think the typical way this works is to @ mention someone which sends them an email & then ping them on slack if they don't review it w/in a certain amount of time, but I always feel at least a little bad about pinging someone on slack.
- Better software to sync local files to servers for development. A lot of devs run linux machines on aws, develop code locally, and then somehow sync their code from local to the dev server. I feel like people often just write their own scripts that amount to using rsync and some kind of system event watcher for file changes.
- More complex reminders. I want task and date specific reminders. So, for example, remembering to buy someone a gift for their birthday. I want the first reminder 3 weeks before and then a reminder everyday until I resolve.
I dunno if any of these ideas are worth solving though. I don't know if I'd pay for them..but they are things I want.