Collection could indeed be used as a workaround(!), but that's not quite their primary purpose. As I said, there's already a page for one thing, where's the harm in making a page for a not very different thing?
It is not a workaround. The feature can be fully done with the things already there, so I doubt that anything new will be implemented. You already get the game into your recommendation/rating box, where you can even set a dismissal to remind you again in 30 days.
And of course, there are collections. Not quite a workaround, but outside of itch, you could also put the game into an old fashioned bookmark folder.
There is no fixed purpose for collections, but it does tell you to "Add this game to a collection to save it for later." Sounds heftily like a reminder to me ;-)
You can even write a blurb to each item of your collection(s), or just use more than one and name the collection by topic.
If they implement a new feature it should be to increase donation level instaed of "buying again". There is currently no way to increase donation level. If you donate 5 and later another 5, your donation level is still 5 and not 10. That is important for games that have individually priced files.