No idea what you mean by "deadband issues" related to this circuit. I presume that the low-pass is intended to filter high frequency noise, e.g. radio signals picked up by the cable. The purpose of the 270k resistor isn't obvious. Primarily it generates a small sensor linearity error.
Input impedance of data acquisition systems can be quite different. Yes, if you have a system with > 1 Mohm input, the buffer can be omitted. But other people might use an ADC which requires a low source resistance in the kohm range. The answer really depends.