Well currently there's a gap of $600 between the 13" 4 port model, and the 16", that's a lot if they're going to become much closer in internal design and performance. But who knows whether that gap is closed by the 14" getting more expensive, the 16" getting cheaper (sounds crazy, but then if Apple can just delete the dGPU because of the SoC approach that's quite a big saving?) or a combination of both (or Apple just deciding it's worked up til now and they aren't changing the prices). As a median scenario how about this:
14" starting $1,999 - same specs as now, 512GB SSD, 16GB RAM. 16 core GPU
16" starting $2,299 - Same specs again, 512GB SSD, 16GB RAM. 32 core GPU
In the above scenario the bigger screen represents a $100 increase as was the case with the identical MacBook Air 11" and 13", while the GPU makes up the remaining $200. Apple saves on the 16" by removing the Touch Bar, and dropping the dGPU for their simpler SoC design.
Then again Apple don't sell themselves short, and these machines could well be more or less peerless on the market so they might think they can charge just about whatever they want for them, in which case $2,899 and $2,999 isn't unthinkable (adjusting for inflation, that's still no more than the 17" MacBook Pro in 2011).