VMWare has no control over how large filesystems are; it only has control over how large a block device to grant to the guest VM. If you want to give the VM guest a larger block device, it might be easier to create a new VM from scratch. (While the
resize2fs(8) tool can resize filesystems, it scares me.) Maybe you can just add another block device in VMWare, so that you can mount it on
/var, wherever it would make most sense for your deployment.
If you dislike how the Red Hat installer has partitioned your guest block devices, that has nothing to do with VMWare, and instead on choices made during installation. A 3gig
/ sounds fine to me, assuming you've got more storage on other filesystems.