The best replacement for vcenter server is appliance.

The best alternatives to vcenter server are rated as following:
★★★★★  appliance
★★★  vsphere client
★★  vcenter operations
★  vcenter operations manager
  esxi

Your alternative for vcenter server is not listed? Suggest!
Speaking about vcenter server, one probably shouldn't forget about vmotion.

Other search terms related to vcenter server and their ratings are:
★★★★★ vmotion
★★ webclient
★ update manager
You have in mind a companion for vcenter server and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of vcenter server in all years. Click on graph for more.
vcenter server
appliance
vsphere client