cmonurz I'm of the same opinion on football as I am cricket. Ideally, for me, someone should be eligible to play for the country of their birth, or that of their parents, and no further back. That said, the rules iz the rules, and if we can 'assimilate' the likes of Arteta or Di Canio or Cudicini, and they want to play for England, and it would be of benefit to the national team, then we should go ahead and do it.
What defines your parents nationality though? That's the only thing that I can see in favour of the grandparent rule.
I'd still rather the rules were tightened up as it seems a bit farscial at times, but even if the rules allow it I'd rather we didn't go down that route. I feel the same with the cricket and other sports too, it's not just football. The whole point is that it's the best a country can produce vs the best another country can produce, not just the best they can attract to live there for a few years.