fdr #44,
Interesting views, no disagreement.
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This particular deficiency is going to be more than a minor matter …’
It might be premature to discuss specific solutions for a deficiency which as yet is not clearly understood (at least publicly).
Elevator effectiveness, yes; but also in normal operation consider the combined horizontal tail surfaces - trim drag. What do you imply with TE tabs; corrective effect must overcome the failed trim condition, but not detract from normal operation.
Alternative thoughts could question why it was necessary to increase the tail area, yet retain the same size elevator. More trim range required whilst the pitch control appeared to be adequate.
The obvious longer, heavier, cg, arguments apply, but pitching moment with varying thrust levels could add another dimension.
Another question is why the trim range was chosen (horiz stab angles), is this relatively large, what are the limiting aerodynamic conditions; high, low speed, configuration, cg, thrust.
Have these changed with the evolving variants.
Background ref;
https://www.satcom.guru/2019/04/stab...and-range.html