As for the luck, sure, there's some of that. But you have plenty of guesses to get to the word if you play according to letter frequency, and always maximize the information you'll get out of a guess. Think of it like counting cards. The goal is to shift the odds as much in your favor as possible. Most games are like that. Deterministic, perfect-information games are a just a small subset of games.
There is a point about luck taking away from the longevity of the game. Unless the developer adds more game dimensions (in the same minimal, non-intrusive way) I kinda think most people will stop playing in a few months
Put another way:
People who say "it's just luck" either don't know, or don't care - but it's neither a correct, nor a clever position.
The aspect I don’t love is that in forcing dictionary words to be attempted, people can rely on that at the end rather than winning through word knowledge. My 9yo plays it and generally does well but was bailed out once by this.