Pretty self explanatory. It's weird that there was a limit on bookmarks in the first place. I'm the kind of person who likes to mark down any interesting things I see or useful systems, planets, and stations, so it's pretty annoying when I have to find some bookmarks to delete when I eventually run out of space. It seems like it would be a pretty simple change to introduce, not even one that needs to wait for one of the big updates.
Additionally, another nice way to make the bookmark system better would be to include folders so you can organize your bookmarks, and with the ability to color code them, or toggle certain ones on the galaxy map (Especially useful if you're like me and want to mark down every ELW you find).
I would also like more bookmarks, unlimited is a bit of a dangerous thing to do though, it depends very much on how the data is stored and loaded. People complain about how long the galaxy map takes to load now, with only 120+ bookmarks there's probably little impact, but if we stretch that out to several thousand even it may start to become appreciable. Having folders to arrange and colour code would be nice, the toggle is a bit of a question mark though, would it need to load all the bookmarks ready to be toggled on or off, in other words could it be used as a way to ease loading time for the galaxy map?
I have an alternative suggestion, and that's to keep the number of bookmarks that can be shown on the galaxy map at any one time to a hard limit, probably 500 would do but it would need to be seen how much it slows loading, but have the ability to load and unload sets of bookmarks depending on what you are doing, that way if your bookmark collection got to the many thousand mark the entire lot wouldn't have to be loaded every time you opened the galaxy map, just the set you were working with at the time.
For instance I have a set of around 150 locations I am interested in for one reason, they are all small bodies under 200km in radius, but often I don't need to see these on the galaxy map, if I am in an area where there aren't any within several thousand light years I am probably working on something that isn't related, maybe Brain Trees, so I have that set loaded into the galaxy map rather than the small bodies set. So rather than a simple toggle, which would require all bookmarks to be loaded to toggle on or off, when I open the galaxy map it either loads the last set I was using or a set I select from an option dialog.