I am completely lost here. Don't people who use eBird simply click the birds seen in the app as they go? On a smartphone, which nowadays is guaranteed to have a GPS in it? What stops eBird from retaining and showing this data, bird by bird? There would be zero additional effort from observers needed for that, just a change in the software.
Because it would require the user to input each bird right when and where they saw it, something I doubt hardly anyone does. I tend to input birds in groups, so I'm not walking around looking at my phone rather than the birds. This means it would be hardly more accurate than a hotspot.
As far as tracks go, I am pretty sure researchers can access them with the permission of eBird.
Any system is only going to be as good as the users who input the data. eBird wants to be used by as much of the public as possible, so the system is designed to be user friendly. A more complicated system will either result in less participation, or simply inaccurate data (and there's plenty of that already).
Now eBird isn't perfect of course, but I don't think adding to the knowledge and time required to use it will help.
How does having exact positions of birds "muddle the map"? If anything, hotspots do that, because with hotspots, there is no way to tell in which areas the birds are common and in which they are rare, because the icon for "one observation 50 years ago" and "20 observations per day" is the same - one hotspot. And if users really prefer to see birds bunched up in hotspots on the map, there is aboslutely nothing preventing eBird from having an option for this while displaying the map - the software behind the map could easily lump observations into hotspots on request.
If I'm looking at a species map for a local area, I don't want to have to click on a million different points to see the observations. And in my local area, a specific personal location doesn't really add anything to the accuracy, because there are accurate hotspots for pretty much everywhere. The problem comes when people don't use them, or don't use them accurately. This happens an astonishing amount, which I think goes to show that eBird doesn't need more complexity for people to mess up.
Finally, when looking at ranges, population trends, etc., I'm not sure what difference it makes rather the bird was reported exactly where it was seen, or with a checklist of other birds at a nearby hotspot.
I must say I don't like how the hotspots are set up exactly. I think having hotspots defined by areas would be great. I really like the way that eBird shows National Wildlife Refuges, with all the hotspots and personal locations brought together, allowing for an easy review of what birds are there at what time of year. I wish they would expand this to all places that have multiple hotspots within the same park, wildlife area etc.