The best replacement for bpmn is bpel.

The best alternatives to bpmn are rated as following:
★★★★★  bpel
★★★★  uml
★★★  epc
★★  archimate
★★  xpdl
★★  idef
★★  activity diagram
★  flowchart
★  bpmn
★  bpml
★  jpdl
★  dfd
★  activity diagrams
  aris
  uml activity diagrams
  epc aris
  sequence diagram
  use cases
  idef0

Your alternative for bpmn is not listed? Suggest!
Speaking about bpmn, one probably shouldn't forget about visio.

Other search terms related to bpmn and their ratings are:
★★★★★ visio
★★★ aris
You have in mind a companion for bpmn and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of bpmn in all years. Click on graph for more.
bpmn
bpel
uml