1) I buy the sets both because they are amazing "parts packs" and because they are spectacular models.
2) Individual only.
3) A nice, big Cathedral (Sagrada Familia-BCN, Notre Dame-Paris, etc.).
4) Pleeeeeease, an UCS Technic set!!! (>2000 piece set: supercar, helicopter, crane, etc.)
5) Return of the Model Team: using technic AND standard system bricks.