I don't know when people with long DLA awards should expect reassessment, it certainly will not be before 2015.
Not every claimant will need a face2face assessment. Whether any such assessment would be carried out in the claimant's home or an assessment centre seems to depend which company is doing the assessment. Capita currently seem to be doing the majority in the claimant's hone, but it is early days yet and things could well change.
Nothing on this board constitutes legal advice - always consult a professional about specific problems