Short story: we [almost] all think virtual keyboards are not convenient, especially if we come from the N900. We currently have two solutions: getting used to virtual keyboards and becoming accurate at typing or Swyping virtual keys while staring at the screen because of the lack of real feedback, or modding the N9 with a bluetooth keyboard with all the cons it implies (battery usage, some keys not recognized, pairing, extra bulk).
What about handwriting recognition? The SGS3 has this feature and apparently it works well. There was also a project for the N900 and, despite it turning out to be a vapourware, it was promising (i.e. working) : http://talk.maemo.org/showthread.php?t=50419. I understand it may be extremely difficult to develop, but perhaps somebody is working on it, and perhaps the work started on the N900 could be used for Harmattan?