Would be great to see, apparently it will take 12 months to get the new trains certified for the tunnel so their timeline seems a bit optimistic still.
Also Eurostar only just started being able to run full trains to Paris again since having issues with the border checks, so I'm not sure how adding more traffic at St Pancras is going to work out, and even if they sort that out there just isn't enough space in that waiting area for more people to still wait there for the hour before your train that they tell you to be there for.