It's not modules which are pulled into core, it's functionality. Functionality that might have been provided by contributed modules (and the code that was added to core might have been influenced by those modules but not necessarly that actual code is reused. For example fields, which was inspired by CCK but was a complete rewrite from scratch). And then these contrib modules don't need to be ported to the next core version.
That said, there is no roadmap in Drupal core development. So it is impossible at this point to answer your actual question.
The only thing that now exists are a number of so called core iniativesinitiatives. That is an area where people are working together under the "lead" of the iniativeinitiative owner to improve Drupal in a specific area. One of those is HTML5 (which might mean that a number of HTML5 related modules might not be necessary in D8) another is Web Services and Context (which means that for example the Context module will be unecessary and maybe parts of Panels). But all that is just speculation at this point. Because even though these iniativesinitiatives exist, it is not set in stone that anything they're working on will be commited.
That is basically the two main tasks that Dries Buytaert (and to a certain degree co-maintainers, iniativeinitiative owners, ...) are doing. They're talking about how Drupal could evolve and what could be done. And then finally Dries decides if a patch is commited or not.
In between, everything depends on if there are people who are interested in something and want to implement/improve/fix some part of Drupal core.