Let me quote the Doctor of Payday 2: Proper planning prevents piss poor performance.
On a serious note: You need deadlines. Without them, you’ll basically get no management of the whole project. I deal with deadlines a lot in my job and there have been so many deadlines exceeded for one certain project that no deadline was set anymore. Instead the management said: “We need to do it, it has high priority. ASAP.” When will this project be finished? Nobody knows.
Think about extending the release schedule from two to three months. Every two months, you get an additional delay of one month for each phase of development. If we take one year now (since release date as of now is late 2015), that would have an additional delay of a half year.
Delays are nothing unusual, just take a look at this year. How many AAA titles have been delayed? GTA V for PC, The Witcher 3, Watch Dogs (and that should have been delayed even longer), Tom Clancy’s The Division, Dying Light, Evolve, all titles that just came to my mind. We don’t know how often these games were internally delayed before they were even announced with a release date. We get to experience the background happenings of the industry, we get used to that treatment of additional information and yet we don’t like it. Why is that so? Because of the disappointment we’re getting.
So would it be better to not know any dates? Maybe. But that’s up to Warhorse studios to decide when they’re going to announce and release the Alpha update. Still if you promise something, you’re doing all you can to deliver it.