MyBB Community Forums

Dont worry. I will not take that personally. And I have one new idea for mybb merge system development but I am unable to post there. Give me a Right to make a post in mybb merge system forum...

This is a good Idea !

I hope they added it in 1.8.x versions

I dont agree with this feature - it could caue many problems - for example I use many highly modified templates

Auto Update can be a misleading name. If you take the approach that Woltlab did with their Woltlab Community Framework, it essentially alerts you of an update for the framework, forum and plugins. The Auto Update has to be initialized by the board administrator. When an administrator decides to update, the framework downloads and installs the update over HTTP. It's basically making something kin to the Steam Client, Battle.net Desktop Client, Origin, etc. They all prompt you on an update, connect to a server and download the update, and installs the update, without the end-user ever having to visit the download section just to retrieve the new version.

While I do like the idea and I really would like to see this, the security breach on GitHub [here] does raise some concerns on how to ensure the update remains secure and a false update doesn't get pushed for malicious intent.

Is there any chance to build a one click update for core files/plugins (like WordPress), in 2.0? Not sure how feasible this is coding wise but it would be cool to have.

Bump.

Feasible, yes. However there is the matter of security to ensure that someone doesn't hijack the update server like they did with one of their GitHub accounts to push a false update so that the attacker could make database backups of any affected MyBB powered forum. (See here: [UPDATED – IMPORTANT] GitHub Account Compromised)
There was much concern over the security vulnerabilities that could compromise all of the boards running this type of update feature, plus a few concerns like plugins breaking, overriding core edits that an administrator made, etc.
Thread discussing an "auto update" feature: http://community.mybb.com/thread-164653-page-2.html

I am against it because of the security risks it presents.

WordPress has recently added auto update feature which do not require admin to perform an update for bugfix release. It's a good feature which will definitely improve the security of a forum.

I believe MyBB should also have similar feature.

Every update has risk. It is up to the site admin to assess the risk and decide when to apply the update. This could mess up any core code changes, plugin incompatibilities, and renaming the admin folder.