i want views from others,the pros and cons of closed and open productions.
Like Overwatch from Blizzard is a closed productions and Project Bluestreak,Unreal Tournament 4 is open production right from the start.
Some thoughts ->
open production:
pros -> you permanently get feedback from the people, you can start building a community from the start and not just when you have amazing stuff to show, bugs and glitches can be found more easily, the player “feels” that he is somehow a part of the game/production
cons -> investing to much time in adding stuff that the community wants (you could loose your actual goals) 
I don’t know how Epic feels about it, but as a Mod it doesn’t seem like the open production of UT4 is good for the community. It looks like the amount of usefulness is much less than the noise.
Hazarding a guess, I’d imagine this is being used as a learning experience by the Epic devs.
UT4 I would not consider open production but rather open source as content and code is sourced from the community. Suitable as the game will be free period and not free to play and pay to win. Personal grip rather annoying being sold that what was once considered the demo is sold as a free game.
Open production is well suited as to filling in Indie needs that a small group can not afford otherwise If your project involves network playability regressive testing can be both time consuming and expensive and could be the single largest expense. Early access or alpha testing in this case is a good way to create hype as well as getting a dirty job done. Don’t know how I feel about it as in most cases as one will generally be paying to play a game not yet done but some are into supporting a game in this manner rather than doing the Kickstarter thing.
Overall though open production means the members on the team are free to talk about the game with out NDA concerns and the development of the game becomes part of the game.
Closed production usually involves large AAA franchised titles where NDA is in effect with any and all information coming from a single channel. The typical reason is $$$ where a bad review can make the difference between a game that does well at the box office or is a complete flop even before its delivered.