Bioware says it would ruin community as an excuse because it sounds better than "We can't do it"
That is pretty much it in a nutshell. Nearly a year ago Daniel Erickson said they were going to do cross-server. Since then they have apparently decided the business case for this is bad. RWZ preseason was only ever intended to be a beta for the code they had (hence the name: preseason
The problem is not that BW does not know what needs fixing (match scheduling, RWZ reconnects, challenge matches, season one). The problem is that, since preseaon was implemented, PvP has dropped off their priority list. (Releasing Hypergates, while nice, does not count as addressing vital structural issues). Will they do something this year besides giving us yet another WZ or a new skill tree with the new level cap? Who knows ... they certainly are not going to tell us in advance.