The best replacement for rpc is document.

The best alternatives to rpc are rated as following:
★★★★★  document
★★★★  rmi
★★★★  soap
★★★  rest
★  http
★  web service
★  message passing
★  messaging
★  ipc
★  ws
★  jax ws
★  document style
★  document literal
★  mapi
★  vfd
★  web services
  corba
  jax-ws
  document style web service
  document style web services
  document soap
  requestbuilder
  document web services
  jms
  requestfactory
  sockets
  doc literal

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

Other search terms related to rpc and their ratings are:
★★★★★ gwt
★★★★★ vray
http
You have in mind a companion for rpc and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of rpc in all years. Click on graph for more.
rpc
document
rmi