Yea, it pretty much would be. I don't know how often you played private but every single server, hell even Nost albeit less so, sucks. Default MaNGOS is crap, and most of these private devs do hack job programming to get things to work quickly rather than properly.
Yea, there are players who will stay private because of it being free, but they will dwindle and eventually die due to there being an ever-shrinking population and this being an MMO game.