Imo i think the next "expansion book" should be a book of magic. They have a lot of material to work with from the previous edditions and it's something people would like to get expanded on.
The following should be taken with a pinch of salt, but on a different, swedish froum, Tomas has stated if everything go's as planned, we may get a pdf release of "The Path to Glory" adventure pdf in June.
I think it would be wise of Free League to aim for 1-2 releases per year from now on, so they don’t release a bunch of material the first 2-3 years, and then we will have to wait five years for the next book.
I would like to see new material instead of reworks of old books. They could do reprints of those 80's books for those suffering from nostalgia. There's enough remakes already in cinema these days, IMHO.