Ah yes, oft to get the error message:
"Something is using the drive but I'm not going to tell you what and I am not going to even let you force the matter. You'll have to close all applications, then I may deign to let you have the device back. Maybe not. You'll have to reboot me, sucker. Bu-wa-ha-ha-ha-ha!"
Windows holding on to USB devices is a bloody PITA. Sure, I can find the lock after a bit of process inspection but I'd hardly call that intuitive.
If you don't know what your computer is doing and why it would be writing to a removable device then that's your own failing. Linux does that just the same too - ever seen 'Device or resource busy'? No help there. Allowing you to force unmount is not a safe thing to do for casual users - you need to know what you're doing and be prepared to accept the consequences of a mistake.
Windows is perfectly fine here if you use and maintain it correctly, and part of that is not installing random background running applications that keep hitting the filesystem and not leaving programs open with files on the device you're trying to eject(!) Explorer windows count as a program in this case. Thumbnail services etc.
If you still have a problem with it and your current solution is a more manual method, just go with something like Lockhunter. Works fine for this situation. Installing a separate utility for this task is another (valid) complaint entirely, in that Windows really never comes with an easy toolchain out of the box. Lockhunter just provides the same functionality as Linux's lsof, so it's worth having.