I agree that their needs to be more information provided but even slow wired should be full duplex (Wireless is half duplex).
Is the wired network 1gig? An ap105 will only support 300M with no other users/interference and that is only theoretical speeds not real world.
So if your users are comparing a 1gig wired network to your ap’s 105 and they are pulling large files then yes wireless is going to seem slow.
If you are using a remote controller and not using local bridging (Matthew point this out in the above post “local drop-off”)that might help a lot but it all depends on where your clients are where the data is they want to access.
If the clients are at the remote site and all their data is at the data center then moving to local bridging isn’t going to help.