+1 but it should be done right. There are a few use case to this issue:
1. The local transfer case (local <-> local), this is covered by Krusader/Cloud Commander since the likely user in this case is the "admin" so it doesn't have to be pretty. For me this is not a big deal, I am happy with the current offering.
2. Remote transfer case (local <-> internet), this is partly covered by File Browser which has user built-in except it doesn't use unraid's user share permission, you need to create your own data path for each user (and you can only set a single root path for each user so you can't have multiple share folders for each user). For me this is what is missing from Unraid that other NASes have, the ability to access via Web GUI with correct user share permissions. This is very useful when you want to download a file from outside your network since you don't need to install any software or set up a vpn, and will please those other users who like pretty interface.
The second issue has another side benefit, in order to do this Unraid will need to support multiple user to Web GUI with limited access!