Yes, although the initial incident was not down to Eurostar, it does look like the handling of it as it affects Eurostar has been abysmal. 10s of thousands pax stranded, but (at least in Bruxelles) huge queues for assistance from those (few) staff prepared to come out and help. Imprecise messages on the website. Hotel rooms soon scarce, and costing somewhat more than the EUR150 budget they indicate. Perhaps just a decisive 'unfortunatley, we're stopping everything for the next six hours and will reimburse you for hotels up to 4 star standard and meals up to EUR 60/day, provided you have receipts. You can get this via the website. And, tomorrow, we will have a 'standby' queue for people without reservations who can take up the places of all those who haven't checked-in at the gates by 45 mins prior'. Yes, the latter would be a surprise to some holding reservations and creates some operations problems in getting through the security in time plus running huge queues at the Eurostar terminals but can ensure that the trains are full on departure, thus maximising through put. Otherwise, we just have the 'you can rebook when ever you like, but there are no seats for the next 48/72 hours, as they've been taken by people who rebooked earlier' which just frustrates people'.
More fundamentally, perhaps Eurostar should consider booking their trains only up to 80% of seated capacity to give themselves and their long suffering pax a chance to recover when there meltdowns of this kind, ie. give themselves a bit of an insurance policy at the cost of less revenue.
Anyway, we will all have views on what Eurostar can do better. the main point is that Eurostar and its regulators in France, Belgium and the UK need to review (once again) their approach to handling major incidents which are (unforutnately) not that rare.