I highly recommend replacing the antenna (or at least opening it up and making sure yours is securely fastened). I did this and have had zero problems--or need to worry about repeaters beyond what is normal for other devices--since. Of course, this assumes it's easy to take the module out. I still wish I had known this before I started, but it was at least easy-ish for where my fan is.
Oddly enough, I've also seen your issue with the in-wall Zigbee devices/repeaters. There are very few of them in the first place (I used the GE/Jasco), and I was disappointed when they seemed to be very unattractive repeaters for a friend whose house was filled with Sengleds and needed more repeaters. 
I'm sure they work well for some people, but your options will be much more numerous with wall warts and similar devices.
I don't have a lot to add for the original poster (besides replace the antenna if you go with the Hampton Bay Fan Controller, but I'd advise for a smart fan switch instead if you already have wiring--this is really a workaround for if you don't). Hopefully the rest of the above is enough to get you thinking!
