I think there was a definite loss in quality from T2 to T3.
Part of the appeal was seeing the stars change from T1 to T2. T3 only had Arnold, and he was basically the same as T2. But really nobody else. Part of it was unavoidable because James Cameron had an affair with the actress who played Rose's granddaughter in Titanic. That destroyed his marriage to Linda hamilton. So I guess it was impossible for Hamilton and Cameron to both be a part of any future Terminator film.
The actor who played the boy has lots of problems with the law including DUI, and charges of abuse against his girlfriend. So we couldn't get the kid either, and are stuck with this new guy. So even though its the same name, its not the same guy. So we have not attachment to him.