What problems?
I see no problem with having a standard NTD, it means that all homes with fibre have the same. Otherwise there would be a complete hotch potch of different NTD's out there and who knows, you buy a house and when you move in you find the old owners have taken 'their' NTD with them and you have to get an RSP to replace it, sometime.
Some RSP's charge a setup fee of, I understand, up to $100 dollars to supply the NBN service, others I know of charge nothing. So looking at my home moving scenario above, you move in to a home with standard NTD, you phone an RSP ask for a service and a short time later, you are online. Some Whirlpool posters report that they have had a connection in minutes. this against moving in, no NTD, contacting an RSP, paying them good money for an NTD and install, wait at least two days and get online.
Really, when you are having some 12 million of these units made, what is the real difference in cost between 1 port and 4. As for the cost, well in the end, the consumer is paying NBN for the unit or they pay the RSP. I just think it more efficient from the users point to have a standard unit installed at the same time as the fibre.
Battery backup, I have to say I have some doubts about that one. It will certainly allow some people to feel more secure knowing they can make a call in a blackout and remember, some people will only have a phone and not take the internet, they will just want the phone to work like it always has. But, the cost to provide to all is silly, it is going to be an option to opt in or out soon and not before time.