When we get lambda meters the discussion of EGT will fade and we'll talk about Lambda (air / fuel ratio) readings.
All I need is Torque(BMEP) & RPM to set power, I think manifold pressure is a very poor gauge of power output, it is only good for letting you know when your manifold will eject in TC engines. The other monitoring equipment such as EGTs, CHTs, FFs etc to let me know its healthy. Knowing the fuel/air ratio going in doesn't really help to operate it.
Its worth remembering that the aircraft manufacturers POH's were written around the standard instrumentation of the time. For a lot of aircraft this meant no EGT instrumentation at all.
And it works just fine without an EGT on these aircraft, the EGTs fitted to them tend to barely work at the best of times along with pilots able to correctly follow the leaning procedure.