The best replacement for viewer is spectator.

The best alternatives to viewer are rated as following:
★★★★★  spectator
★★★★★  powerpoint
★★★★  crystal report
★★★★  plug in viewer
★★★  task manager
★★  vnc
★★  visio standard
★★  interactor
★★  edrawings
★  firestorm
★  go to my pc
★  audience
  visio
  adobe reader
  iteleport
  vnc server
  ultravnc

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

Other search terms related to viewer and their ratings are:
★★★★★ chime
★★★ permission
★★ knocker
You have in mind a companion for viewer and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of viewer in all years. Click on graph for more.
viewer
spectator
powerpoint