As Veej says, you need serious handwavium to get him to 2010, but assuming you did, one consequence would likely be no debates. Charlie played very well on telly and Cameron only pushed as hard as he did for three party debates because he thought Clegg was a no-mark with no charisma, as was to be expected pre-Clegg-gasm. With a longer serving big beast who the public liked the image of leading the yellows, the debates might not be floated by a Tory party looking for a majority.
As Veej says, you need serious handwavium to get him to 2010, but assuming you did, one consequence would likely be no debates. Charlie played very well on telly and Cameron only pushed as hard as he did for three party debates because he thought Clegg was a no-mark with no charisma, as was to be expected pre-Clegg-gasm. With a longer serving big beast who the public liked the image of leading the yellows, the debates might not be floated by a Tory party looking for a majority.