The Board often behaves in mercurial ways, and, in my opinion, is perfectly capable of going down the wrong rabbit track. That said, they have some of the better metallurgical and structural people in the industry, and, although I have no first hand knowledge of this accident, I would expect their work to be rather solid in this regard.
Regardless of all of this, I will say that based on my intimate experience with Franco-NTSB relations during the Roselawn investigation, the Board is very unlikely to be influenced by French pressure. Indeed, it is far more likely to yield the opposite result.
As far as the certification limits on vertical stab loads, I had no idea prior to this accident that the stab was not structurally designed to handle rapid rudder reversal. Once I read the rule in Part 25, it was painfully obvious...I just never looked at it before, and I certainly never heard it discussed in training with any airline.
This among many other cases has reinforced my belief that a genuine ATP license should require a comprehensive education in both Part 121 and Part 25 rules (and/or the EASA equivalents, depending on your country of issuance), including the means of compliance acceptable to the authorities and the history of accidents and failures that promulgated the rules in the first place.
For example, how many of us realize that the flight director pitch guidance during a go-around is predicated on the engines being spooled to approach power at the initiation of the go-around? The Air Canada crew at Fredericton apparently did not; they followed the pitch guidance promptly, even though the engines had been at flight idle when the go-around was initiated.
We have been fighting this battle with regard to icing certification for years. Many pilots continue, with substantial help from the authorities and the operators, to conflate holdover tables for freezing precipitation with certification to operate in same. Not the case at all. But beyond that, the accident history is laden with cases in which the pilot did not understand the criteria to which either his airplane was certificated, or to which the approach aid was certificated, or to which his ops specs were approved, and so forth.
Perhaps a little less "unencumbered solutioneering" in various training departments, and a bit more thorough exploration of the regulatory criteria and constraints, would go a long way in this regard.