The best replacement for p2p is client server.

The best alternatives to p2p are rated as following:
★★★★★  client server
★★★  scene
★  f2p
★  torrent
★  dedicated servers
★  p2e
★  usenet
★  p28
  torrents
  riaa
  mpls
  bittorrent
  b2p
  dedicated server
  gpon
  p2p
  bit torrent
  b2b
  not 2 p2p
  direct download
  grid
  newsgroups
  irc

Your alternative for p2p is not listed? Suggest!
Speaking about p2p, one probably shouldn't forget about tor.

Other search terms related to p2p and their ratings are:
★★★★★ tor
fast downloads
You have in mind a companion for p2p and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of p2p in all years. Click on graph for more.
p2p
client server
scene