Need ans of 2nd point in simple language.....
You can use performance tuning tools in the guest operating system for software profiling. You can identify and improve processor performance problems. This capability is useful for software developers who optimize or debug software that runs in the virtual machine. but then when it's in use, you face certain limitations like the one which is mentioned in point no 2 in your list
Ref: VMware vSphere 5.1
4. You cannot use migration with vMotion to migrate a virtual machine that uses a virtual device backed by a device that is not accessible on the destination host. For example, you cannot migrate a virtual machine with a CD drive backed by the physical CD drive on the source host. Disconnect these devices before you migrate the virtual machine.
5. You cannot use migration with vMotion to migrate a virtual machine that uses a virtual device backed by a device on the client computer. Disconnect these devices before you migrate the virtual machine.
Let's say we take an example of virtual CD/DVD drive of your VM, this has three options,
Point number 4 in your list is referring to Host Device, if your VM's cd/dvd drive is set of Host Device, that means it has local dependancy, so it cannot be vMotion migrated. even if I try, it will give me following error
Similarly if my VM's virtual hardware component is dependant upon physical hardware component on client device, that will also face trouble being vMotion migrated.
See if this helps.