Ultimately it's down to the individual user's storage needs but I find there is a massive difference between 512GB and 1TB in practical terms - with 1TB I can probably carry my whole iTunes music library, a bunch of TV shoes, plus a local mirror of my cloud stored work files of a reasonable size, plus I can install all the apps I want (including a few games) and still have a decent chunk left over.
Extra CPU cores are nice of course, but won't be game-changing for any tasks, they would just in some cases make them complete a little (probably seconds) quicker. Whereas the time you will have to spend dealing with a full SSD can take hours if you regularly bump into capacity limits.