I have mixed feelings about it. On the one hand i don't have an inherent problem with the idea behind it, i.e. forcing the traitors into taking action instead of camping for several minutes. I know that is the preferred tactic of some individuals. However I find, myself at least, sometimes making silly mistakes due to the pressure of the smaller amount of time traitors are given. I have, on several occasions, still found that I have to lead the way with the kills even with 3 traitors on my side because after 4 minutes no one has done anything.
Also, I do agree with the point that the innocents can feel a bit lost not knowing exactly how much time is remaining. For instance, 10 seconds could be remaining and they are forced into a fight with a traitor who has the advantage. However not knowing they only need survive for a few seconds they will most likely fight back instead of simply running.
Having said all that, for the most part, haste mode hasn't really hindered my gameplay all that much. Like I said there are the odd occasions where fellow traitors will still camp because thats just the way they play (albeit a very shit way to play!!!) So my opinion is that the Haste Mode matches should be a random occurance, maybe 1 in every 3 or 5 matches. And for normal matches the time limit should be lowered to around 10 minutes, just to give the traitors a bit more encouragement to get off their arses and feckin' do some killing!