Kid Charlemagne
I am the Very Model of a Modern Moderator
I see most of the same things that we saw with the beginning of 3rd edition. Monster books, because you can never have enough, and especially to fill in the gaps. Ditto with magic items and spells - you can never have enough. Missing "core classes" especially if things like the Druid aren't in the PHB. Adventures, because we always need those, especially at the beginning of a new edition.
I don't think we'll see too many compilation books - there won't be much to compile yet. I think we'll see some new rules, just like Relics and Rituals introduced new Ritual Magic rules in one of the very first d20 books, but I don't think we'll see anything on the scope of Hyperconscious or Mindscapes within the first five months. Someone will probably try to stake out the psionics design space before WoTC gets there, but I don't think it'll happen within that timeframe.
I don't think we'll see too many compilation books - there won't be much to compile yet. I think we'll see some new rules, just like Relics and Rituals introduced new Ritual Magic rules in one of the very first d20 books, but I don't think we'll see anything on the scope of Hyperconscious or Mindscapes within the first five months. Someone will probably try to stake out the psionics design space before WoTC gets there, but I don't think it'll happen within that timeframe.