I sincerely hope that Oppo does not add bass and treble controls. I am a potential customer and I do not want to pay for features that I will never use and could potential downgrade the functionality of the unit. I don't want a balance control either. There are plenty of products out thee for people who think they need that kind of band aid.
The price of the amp is already set in stone, already being sold to the public.
Whatever revisions they make, or whatever features they may ad, will not cost the consumers any more money.
They have a certain amount of R&D funds set aside for specific attention to the HA-1 as needed.
This is yet another thing that is great about Oppo Digital.
Not many companies out there will continue to develop a product for the purpose of improvements beyond bug fixes after it is released for sale.
Some of them don't even get the bugs fixed. Not that the HA-1 has any bugs, but just sayin, in general...
I also don't think it's necessary to add they controls you mention, but if enough people ask for it, they may add it.
However they would never add anything that would downgrade the functionality of the amp.
If they were to add such features, they would be added in a way so that they can be completely bypassed if the user doesn't want to use them.