In FFVII itself Zack has no character really aside from being some guy Aeris apparently dated and the guy who saves Cloud. There's really nothing to him other than that. I could see feeling some sadness in that sense since he's a character who's most important role is having his life unintentionally usurped by someone else when he dies but honestly we never know him well enough for me to care beyond simply acknowledging that this guy has supremely bad luck in the game.

As for the rest of the compilation, well... he's not necessarily bad in Crisis Core, but there's nothing that really made him stand out to me. He's a bland character in a game filled with so many bad characters, poor writing, and questionable retcons that it's genuinely hard to give a trout for me. The entire Compilation is that way though.