If you adding more VMs it may be better to create a new volume instead.
Typically more smaller volumes work better than one HUGE one.
It allows for more concurrent I/O to be processed. Kind of like two people working same problem vs. one doing it all.
Also if you have installed the VMware Storage Manager appliance that will do the entire resize process for you or help you create a new volume on the array and mount it to the ESXi servers.