The problems I see with flipped, game-based teaching

A few days ago I read with some interest this article by Paul Rogers on how to flip the classroom and use games to motivate learners. I have to admit the whole ideas sounds really exciting to me: let the learners do the input at home, at their own pace, and use classroom time to practice, clarify and use the language — with games! What more could I ask for?
I am sure this approach is based on sound theoretical — and practical? — knowledge, and it could very well be that once I try it, I’ll completely change my mind. So take this post for what it is: a collection of my own personal thoughts when, reading the article, I put these ideas next to my everyday teaching situation. First some background information: at the moment I mainly teach monolingual classes of adult students in evening courses. I see each class typically once a week for two hours, between three and nine months in total.
So when I read about flipped, game-based teaching the first three objections that come to my mind are:

1. My adult learners often struggle to find the time to come to class once a week. I always try to encourage them to spend at least another two hours a week (ideally divided into small chunks many times a week) practising and being exposed to English at home, but most of them have jobs, families, commitments that make this task very difficult. So when one of my students comes in apologising for not having had time to revise or practice, I always try to be lenient and understanding. After all, we all know what it means to juggle between home, work,  family, the gym, English class… So my first question is: how can we expect our learners to have the time, concentration and willingness to tackle new material at home? I might be too pessimistic, but if I look at my students, I think about 80% would be demotivated by this mammoth task after only a few lessons.
2. I use games in my lessons sometimes, I find them an enjoyable and motivating way to use, practice or revise the language. However, I have had more than one adult student feel demotivated or complain about this to me or to the DoS. Luckily every person is different, some learners do enjoy games. However for some adults time in class spent playing games might seem like a waste of their time, not to mention their hard-earned money. So if the games are once in a while, these students might accept them and even enjoy them, but what could happen if they become the norm?
3. Last but not least is the problem of competitive game + monolingual class. I don’t know if you have ever experienced this. Personally I have noticed that, with all types of learners, from YLs to adults, from beginners to advanced, once the competition kicks in they forget about English end up using L1. I can set as many rules as I want, encourage them to use English as much as I want, and even draw a sad face on the board next to the word “Italian”. If they are focused on winning the game, if they need to communicate with team mates, they will invariably end up switching to the comfort of their L1. And in my opinion this is a big deterrent for using such games in a monolingual classroom. I know there are non-competitive games, but if you base your lessons entirely or mainly on games, how can you avoid competition?

So my questions to you are: have you tried this approach with adult students? Did it work? How about monolingual classes? If you think about your teaching situation, would you raise similar concerns, or do you believed a flipped, game-based teaching could work in your case?
I can’t wait to read your comments on this.

Cover image from http://blog.ed.gov