Notice how Honda refuses to offer cash rebates to move Accord product? They will not tarnish the brand like that and this partially explains why Honda vehicles frequently exhibit industry-leading resale values.
I think the Altima stands more to lose than the Camry from the 2003 Accord. I, for one, cannot stand Detriot interiors and it seems Nissan used the Big 3 as "inspiration" for the Altima's plasticy cabin. The new Accord will probably feature an exquisitely tight and refined interior space for a midsize sedan.
Nissan may win the horsepower race, but it seems the general public doesn't place HP very high on their evaluation list. Consider that about 70% of all Accord and Camrys are sold with I-4s putting out 140-160hp.