it's true that van nistelrooy doesn't score enough in the big games (one in four against us, one in five against the arsenal, couldn't score when they needed it in the CL last year) - and that is the biggest problem in his game.
however the heskey van nistelrooy comparison becomes problematic when you consider that van nistelrooy, despite not scoring too often in the big games, has scored more than four times as many league goals as heskey since august 2001. not to mention 11 goals in eight champions league games this season.
when heskey starts scoring at that rate i'll go easy on him for not scoring in the big games.
his goals against roma and blackburn may have been important, but may not have been so crucial had it not been for his unbelievable misses at other points (e.g. i remember him slicing wide of an open goal in the first roma match in that CL group).
and in trying to point out that he has scored important goals this season, you have merely underlined that in our current form, every goal is crucial to us. you have just listed three of his four goals for the season.
of course it is likely that none of them will turn out to matter, as we will not qualify for europe with them, and wouldn't have got relegated without them...