The larger number of IDA-8 reviews is simply due to the affordability and highly reviewed quality. Audiophiles, when they move to higher level gear more often than not go to separates, rather than integrateds.
Regarding the IDA-16; It is easily the match of units costing many times more. Michael mentioned enjoying his ST-10, and the amp section of the IDA-16 is most similar to the ST-10, except with MORE power.
It would be hard to think of any Integrated that would meet your needs as well at anywhere close to the price point.
As a dealer, I have spent considerable time with the IDA-16. Most of it was through a pair of large floor standing speakers (VMPS RM-40) and in a 20 x 30 room. The 200wpc ran those speakers like they were easy loads, so the power is there.
Your primary challenge is your listening position, and wishing to get a "near-field" experience with a "far-field" position.
As the sound leaves your speakers, it begins to disperse and reduce in energy. That is, the sound energy spreads out and as it does loudness reduces. As well reflected sound increases in a relationship to direct sound.
This then means you need to use a higher SPL to achieve clarity and detail.
The IDA-16 has not only significant power to allow this, but has the transparency and detail at higher volume levels to help you with your goals.
There are other methods and means too that would help, such as choosing a speaker with less directivity (dispersion) such as a Line Array, or some planar and ribbon type speakers with a reduced directivity.
In any event (keeping in mind I am a dealer) I think you will find the IDA-16 one of, if not your best choice, especially at that price point. Many high quality DACs cost that much, and with the IDA-16, you get the whole package.