My main interest was in demodulation. With its full HF coverage lack of proper AM detector seems a major feature lacking in the rig. NBFM comes as bonus with this chip. TDA1220 has an internal? AGC for AM. I feel simple addition of this add on board will? make uBitx a very fine Gen coverage Rx.?
FM can be done possibly shift the BFO to 15MHz? phase modulate and triple it for decent deviation and modulation index and pass the signal thru 45MHz filter up reverse. As you rightly say cost and complexity will go up and we still wont be able to beat a Baofeng and a 2nd hand 817 will be a better option.
With the new Ver 4 boards and connectors across the 12MHz filter I foresee people trying out parallel CW xtal filter mod soon hence thought about a plug in board.