I've read that there's supposed to be a new profile manager. I think it's great that this area is being expanded.
I would really like to see the option in the future to create, move, save, and use Firefox profiles flexibly in any location.
This would also have the advantage of allowing users to save the profile folder to a specific location (e.g., D:/), so that if the system (C:/) ever fails, their Firefox profile is still safe.
It would also be practical if a single Firefox installation could recognize and use other Firefox profiles simultaneously.
(For example, if you have a portable Firefox version installed somewhere, it would be very helpful to be able to access and use those profiles after telling the software where the portable version is installed.)
But it would be just as good if, when you plug a USB stick into the computer and start a portable Firefox version, Firefox checked for a full Firefox installation and started that one first. The portable Firefox only needs to be started if no Firefox is installed on the computer. A full Firefox installation is (usually) faster and more efficient.
This would have many advantages.
One of the most important advantages is that you would only need one Firefox installation but could use multiple Firefox profiles. This is important if you want to keep your workspaces (personal vs. work) separate or if you want to share a profile with someone but not have them see other content.
I've read in some articles that many people find it more secure to store profiles in only one location, on localhost. These people can still do that, of course.
If you maintain your PC and have security features enabled, security should be guaranteed. However, it might be good to be able to expand the master password. That is, to encrypt not only the password file, but perhaps the entire profile folder.
In any case, I think it would be very good if Firefox offered the option to create Firefox profiles anywhere, because it would probably save many people time. Especially when working with different types of data (freelancers or web designers), it can be very helpful to create a separate profile for each topic or client. And it would also be very clear if the Firefox profile could ideally be stored directly in the topic or client folder.
I think that would be a great feature.