It's great to see these developments.
I think what World Rugby really needs to do now on the back of it is to expand the world cup to 24 teams. It provides for a fairer schedule (4 team pools avoids 4 or 5 day gaps between games), increases the number of knockout games (with a round of 16 after the shorter group stage) and most importantly will encourage further development of nations around the fringes of qualifying.
In terms of competitive depth Portugal is currently ranked 24th in the world, and they were at the 2007 world cup. And there's a number of countries ranked below them that are on the way up such as Brazil, Kenya and Germany (if they sort their issues out). Ideally you'd go to a 28 team and finally a 32 team tournament when reasonable to do so.
Having one weak team in each (or some) pools is okay and I think the quality of the 24th team by 2023 will be good enough to avoid 80+ point thrashings (at the very least I don't think you'd have more of them than in some previous tournaments). The main challenge would be in improving the teams ranked from 10th-18th. You don't want a situation where in some pools you have a certain winner or a certain top 2. There's still a bit of improvement needed from the likes of Italy, Fiji, USA, Japan and Georgia etc to ensure that. But it doesn't seem impossible by 2023.