Not a good sign, not at all.
While I dont pvp, there are others that do. D2 had a very active pvp scene in all forms, team pvp, low lvl pvp etc. Arena sounds like a great feature that they realy should include. All those whining aout pve balance being affected by pvp : so what ? pve will be easy anyway. Look at d2. Once you know the game and have played trough it a few times, you can play it naked with no skills. I dont think that D3 will be different.