I don't use remote start much, so I can't really attest to that.
With a person in the seat, they warm up fine, I would say typical as compared to other heated seats I have had. Haven't worried about no person in seat, again, I rarely use remote, although we are approaching a time where I may begin to do so.
A person in the seat is going to speed up the heat process with both the heat of their tush and the pressure pushing the seat surface against the heater.
My wife hasn't complained about failure to heat, she does turn her's down after 10-15 minutes usually.
I can think of some humorous off color comments about this, but don't want to upset the censor police. In the end, I think much of the issue may be a personal preference/sensitivity, although the person with a portion of his seat not heating sounds like he has a real issue.
2015 Canyon SLT, Copper Red, 2WD, CC, SB, V6, Tow, blk leather, factory spray liner, safety pkg, generic roll up bed cover.