Yeah, EVERYONE else connected with the series has been very firm that there will be more full seasons--with "full" meaning three eps. I don't know what Freeman is up to, but I'm sure we'll be hearing from Mofftiss as soon as reporters have a chance to talk to them.
(If I were Freeman, I wouldn't be so quick to take myself off the table, if indeed he every did, because now that Watson isn't living at 221B, they could do a few episodes without him, or with very little of him. There were, after all, at least two stories in the ACD canon narrated by Holmes that did not have Watson in them.)
ETA: Come to think of it, it wouldn't be the first Sherlock Holmes series to switch the actor playing Watson mid-series.