If you have some app for something that you like and are looking for other similar apps, is that an appropriate question?
This is still a list of X question, just rephrased. Consider it as a cooking.se question: 'I like macaroni and cheese, what are some other macaroni and cheese recipes?' It invites poor answers that have a subjective basis (especially here where it would often be localized to a particular handset).
I'm going to say that this depends on how specific it is. At the least, it should be community wiki. If it isn't specific enough, then it should be closed.
My opinion: If the question specifies how an app would be "like" X, as in providing a list of required features/constraints, then that's OK.
But in that case, you don't really need the "App X" in there. I suppose it doesn't hurt, but you could just say "I'm looking for an app with these 10 features."
Unless these questions are significantly constrained, there's no appreciable difference between them and What X app should I get? questions. I'd at least be suspicious of any and all questions taking this format, as they are likely to be treated as polls.