It's not suppose to end at 7500rpm. It's suppose to keep going upto 9k rpm. From the mods for the 2.34, the powerband was shifted all the way to the right and then you are comparing it to a motor with the powerband not shifted to the right as much. You can even see the 2.5 starting to run out of breath by 7k rpm while the 2.34 looks like it wants to keep going.
I have been in Doms 07 STi with his 2.34l motor with practically nothing done to the heads. It's a seriously smooth motor that while it doesn't have massive power before 4k rpm, it has pep in that range. It just WANTS to rev. Aside from the poor gas milage it gets, it makes for a fantastic DD IMO.