I agree with those points but there has to be a risk that a pro-Remain house could obstruct any Brexit deal as originally envisaged by the Referendum outcome (leave means leave etc.) It is the Remainers who have the most to gain from allowing a Parliamentary vote on this.
The other thing is each party has their own agenda, the Labour party, Lib dems say there should be no cap on imigration, the Tories say there should be, the single market etc, whatever is put on the table in the commons you will never get an agreement across the house, the voting will be all over the place.