It's still the same engines from 2002 to now. A 2.5 and 3.5L engines. Because Nissan has tweaked the power in the cars to keep it competitive with the rest of the class doesn't make this a new engine. And what other companies haven't incresed HP over the course of 8 years with the same motor? It still has the same engine, just tuned differently. That's like saying the small block V8s in the Chevy pickups aren't the same as those in a Camaro or Vette. By your reasoning GM makes about 10 different V8s because their power is different based on where they're installed. It's the same architecture. In the Altima's case boosting HP by 30 doesn't make it a different motor.
Well, it's basically "the same architecture" in the 3.7l motor that puts out 330hp in the Z and G. You may be as contemptuously dismissive of that as you please - it's an open forum - but your underlying suggestion that Nissan is somehow trotting out the same old tired mill year in and year out is starting to look a bit absurd. Even the jump from 240 to 270 in the Altima is nothing to sneeze at. Aftermarket tuners spend thousands chasing less of a quantifiable gain in power than that.
And also consider: 1) most manufacturers DON'T introduce a brand-new ground-up motor with each generation of their midsized family sedans, and 2) it was Nissan's Altima that we have to thank (or curse, depending on one's view) for the phenomenal power available in this class today. It was the first shot fired in the midsize import HP wars and positively SMOKED everything in it's class when introduced.
I'm not sure what your particular agenda is in attempting to characterize the 2010 Altima as a barely cosmetically altereder version of the 2002 model, but as I said, it doesn't accord with reality. I think the Edmunds review sums up the nature and status of the current vehicle quite well. You'll understand, of course, if I place slightly greater weight upon their editorial opinion than I do upon yours.
Jaeger