If you're in Australia - stay with fixed-line when forced to switch to NBN or drop fixed-line entirely for home internet ?

I can't decide if I want to switch from ADSL to the NBN still on fixed-line (copper) to where I live or drop fixed-line entirely and use wireless broadband exclusively for my home internet connection.

Help! I get really pathetic mobile phone signal coverage so concerned that as more and more people choose to dump fixed line all the wireless services will become saturated and effectively no better than what's on offer now.