I bet most people will want to use your amp with balanced outputs DACs, in which case 4V/14dBu will be the standard for consumer level units and your amp will have 6dB too much gain, ie 6dB too much noise (audibility of which depends on the transducer alright, but also on the DAC output noise...) and also 6dB of potential clipping toward fullscale (=danger for the ears and tweeters).
Some users might also want to use pro level balanced DACs, with higher output level options such as RME (19dBu, 11dB over sensitivity here) or Benchmark (27dBu, 19dB over sensitivity), further increasing the mismatch and potential pitfalls. Using higher output levels not only opens the potential for a higher dynamic range (which you might not need depending on the situation, as you noted), but also improves immunity from external interference (which is often useful in real world situations). Furthermore, many pro units will simply not give you any "consumer level" output options (many pro DACs and processors do this, BSS ones for example, among many others. In fact having variable analog output level options is quite uncommon in the pro world), leaving you with digital attenuation as the only option, with far from ideal dynamic ranges as a result. In many cases that is going to produce audible hiss on any transducer.
Gain structure optimization is what matters, much more so than the individual performance of a given piece of equipment in the chain.
Having a range of selectable gain/sensitivity options to accommodate all these common scenarios would be useful here.
That is what Benchmark does with the ahb2, and what I would call a "much wider range of options available" scenario, and appropriate for a premium amp sporting SOTA purifi modules.
Now if "the rest of us" are people using unblanced 2V DACs then alright
