I wouldn’t say that it’s a “bad” thing, Anon. Zac and Troy do have quite a few things in common, personality-wise. They’re both absolute sweethearts, giant, lovable dorks, have a level of modesty that is both deeply endearing and often borders on concerning, they love sports and theater, and they’re always willing to see the good in others.
And, with the exception of one certain rather distinctive feature (the beauty mark he had near his jaw)
they do have the same face. It helps that, although Zac is clearly older, he’s aging very gracefully.
While Zac has made great strides to prove himself as a serious adult actor capable of holding his own among his peers who didn’t achieve what was, essentially, overnight fame by starring in a subpar Disney Channel Original movie, (and there are still people out there who insist that he can’t act despite him more than proving himself) he looks back on his High School Musical days with nothing but fondness. I can’t speak for him, but something tells me that he wouldn’t mind you still seeing him as Troy.
Personally, though, over the years, I’ve made a very clear delineation between the two of them in my mind. Zac is Zac to me and Troy is Troy. There’s absolutely no blurring of the two, even when I’m hearing the dialogue that I write for Troy spoken with Zac’s voice, and picturing Zac acting as Troy, in my head.