Fair call nophead.
That said, we could use a 5V gate drive circuit (there is 5V available off the Arduino Due header), rather than using 12V as STB suggested. IMO using 12V doesn't really buy us that much better performance, and with people using voltages like 18-19V and 24V much more often now, relying on 12V being available (without us specifically providing it - as it's not directly present on the Due) could be a problem. Providing drivers that can happily handle anything up to 30V could mean we spend more on driver circuitry than is really necessary. Yes it's a bit of a compromise, but it's a better compromise than we currently have in place on boards like RAMPS.
PS: Re: Cheaper FET's. I'm now seeing pricing for the IRLB8743PBF below the US $1 mark at various distributors for 1-5 off quantities, though places like e14 seem to be lagging this unless you buy in volume. I personally would prefer to see electronics with a semi-decent MOSFET as the primary option defined in the build instructions, mainly because cheap overseas volume-based knock-offs tend to use whatever the default build spec is. Admittedly, part of this is because I've seen so many people having issues with high current loads on things like the STP55NF06L's on the RAMPS boards. Even if driven with a 5v driver, the STP55NF06L's would still need to dissipate more heat compared to the IRLB8743PBF as the STP's RDS(on) is 5x the IRLB's (@Vgs=~5v).
That said, we could use a 5V gate drive circuit (there is 5V available off the Arduino Due header), rather than using 12V as STB suggested. IMO using 12V doesn't really buy us that much better performance, and with people using voltages like 18-19V and 24V much more often now, relying on 12V being available (without us specifically providing it - as it's not directly present on the Due) could be a problem. Providing drivers that can happily handle anything up to 30V could mean we spend more on driver circuitry than is really necessary. Yes it's a bit of a compromise, but it's a better compromise than we currently have in place on boards like RAMPS.
PS: Re: Cheaper FET's. I'm now seeing pricing for the IRLB8743PBF below the US $1 mark at various distributors for 1-5 off quantities, though places like e14 seem to be lagging this unless you buy in volume. I personally would prefer to see electronics with a semi-decent MOSFET as the primary option defined in the build instructions, mainly because cheap overseas volume-based knock-offs tend to use whatever the default build spec is. Admittedly, part of this is because I've seen so many people having issues with high current loads on things like the STP55NF06L's on the RAMPS boards. Even if driven with a 5v driver, the STP55NF06L's would still need to dissipate more heat compared to the IRLB8743PBF as the STP's RDS(on) is 5x the IRLB's (@Vgs=~5v).