Then you mustn't have watched their Lindy hop section in the SD carefully. Apart from Piper Gilles, no other lady ice dancer, not even Tessa, can pull off that level of goofiness so brilliantly. No sad face to be seen.
https://m.youtube.com/watch?v=6tK3ULlc7LA
And during the whole middle part of the Mozart and towards the end of last year FD, she smiles and/or look very serene. In the Paso, she looks smoldering and hot. She is a great actress. Guillaume could improve his facial expressions though, he's better expressing himself with his body.
People just repeat what they keep hearing without making the effort to actually check with an open mind. Gaby is mono faced weak skater who is dragged around by Guillaume, they have no range when they demonstrated range within their SDs and music choices in their FD, they're prone to errors when in 2 years they messed up couple of time only and so on and so forth. They certainly can improve in many areas but I think people confuse their own personal tastes with what actually is going on on the ice.