In fact SusanP, Tier 2 is the so-called 'skilled' migrant visa. So why change these rules?
You do realise that most of these immigration changes have been made following consultations with firms in the UK? It's because some weren't as skilled as others. Or they commit crimes in the UK and it's not in the publics interest to let them remain. A crime can delay their ILR, which then might take them over the time limit for that visa route.
Tier 2 (General) has been made easier for international students and they are no longer put at a disadvantage because companies no longer have to carry out resident market test for them. There is no limit to these "unresticted" CoS for Tier 2 (General). International Students are now on a level playing field with the UK and EU students, to ensure the companies can pick the best and issue a Tier 2 (General) without delay.
For those students that can't find a sponsor. As the PSW visa (for those who couldn't find a firm to sponsor them) has now been removed, the same with Tier 1 (General), they take their skills home. Unless they marry a UK or EU citizen, or someone with ILR OR they qualify for one of the two new Tier 1 visas.
The past is the past. Perhaps Labour messed up. Perhaps large numbers of people coming here for the past decade and a bit are lower skilled. NONE OF THESE CHANGES WILL AFFECT THEM.
Really!? Do you want to think about that? Someone with your username posts on immigrationboards.com and can read all the changes that affect those already in the UK, just as easily as I can. Hint, one of these is what you did and has now been stopped.