In a normal context, no, it wouldn't be. What makes it corruption is:
1. It's done surreptitiously, often maliciously. If the game consisted of only the current RL scenes, minus the Alicia brainwashing context, then yeah, I'd probably be more inclined to call it a teen drama rather than corruption.
2. It's clearly a prelude to other things that are sexual (e.g. cheating).
3. It comes at the expense of MC's existing lifestyle and social connections, as we see in various scenes, as well as things she starts out caring about (e.g. academic grades).
4. The changes go deeper than just fashion sense, some of the values being instilled are generally considered negative: superficiality, opportunistic relationships, sexism, tolerance for bullying etc. Now, what is considered corruption is at least somewhat subjective, but I think it's safe to say that these traits are not something that the average player of RPGM games finds agreeable. Hell, there are even scenes where MC loses interest in game development.
The hair, the glasses, the shoes are all normal things, but in the context of a nerdy person unwittingly being changed into something very different, they're all a canary in the coalmine, and I'm glad this game takes the time to be comprehensive with the process. The sexual content so far is okay, but if I wanted to see a heroine being harassed and blackmailed, there are probably hundreds of other games I could choose from. That's not the main draw here.