You are using conflicting logic, for example the Xenporta thread is a highly successful thread, therefor it is not good. As for organization, nothing will change that on successful threads, even with infinite scrolling, it is still a wall of text that needs to be read, which is more often than not the barrier of most users when it comes to finding stuff.
To impress guests and search engines .... excellent content must be created and easily found.
Software does not create the content, administrators have a responsibility here to engage users to create good content, either via having an engaging topic, or kickstarting activity via controversy or whatever. How you choose to organize your content can differ, but xF does a pretty good job of making the content accessible for search engines. Also proper use of thread prefix, categories and subforums will make your content more easy to find.
In 2013, forums just encourage back and forth banter which often isn't good content.
Forums, also called discussion boards, are meant for that sort of behavior, its called a discussion. Whether or not there is an interest for that is kind of irrelevant, cause you are saying that forums needs to be something else in order to succeed, which just isn't the case. Maybe you are just looking for something else other than a forum.
