Scotland's heavy loss to England today means they cannot pass Ireland next week as they won't pick up points against Italy and Ireland have enough of an edge that they can lose by 15 or more at the Aviva and still retain their World Rugby #4 ranking by a mere .22 points.
Ireland control their own destiny. If they beat England by any margin they retain 4th.
If Wales wins in Paris next week, and England beats Ireland in Dublin, Wales will leapfrog from 7th to 4th, displacing Ireland from Pot 1. The margins of victory are irrelevant because both teams are on the road, which makes wins more valuable.
So when World Rugby does the RWC draw in May we'll see New Zealand, England, Australia and Ireland/Wales in "Pot 1". "Pot 2" will likely contain Scotland, Ireland/Wales, France and South Africa.
Here's a description of the 2015 draw to refresh on how the seedings flow through "pots" into pools.