And the reason I think this is wrong is precisely the effect that the debate had - that many, many people not in Scotland now have a positive view of SNP leader Nicola Sturgeon**
And as several English papers have been running scare stories about the SNP, and the terrible effects it would have if there was a Labour/SNP agreement, this will probably have a small, but significant, effect on voting patterns.
If the SNP were likely to gain 6 seats (as they did in 2005), then this wouldn't be an issue. But as long as we have a situation where regional parties can form part of the UK government, and particularly while the possibility of deals with those parties is being used to scare people off the larger parties, they need to be put in the spotlight so that people can see what they're going to get.
*I didn't watch them myself - but I did keep up with the Twitter discussion and the response in the media/blogs today.
** Many English people would now rather like to vote for her...
Original post on Dreamwidth - there are comments there.