I am neither a teacher nor student of gemara - aside from a class in "Aggadot Chazal" as part of my seminary year.
I am, however, a chumash teacher for the last two decades, and mother of boys.
What I have observed is that gemara is extremely complex -- layers of presumed understandings, discursive tangents that take you far away from the main discussion, plenty of ambiguity, and very tightly packed. Aside from the aggadata section, it can also be somewhat boring. There's a lot of talking heads.
For some kids, the text just washes over them, and they lose track of the main discussion - or why it's personally relevant.
In a sense, we're requiring all boys 10+ to enter law school. While this may be great for those who naturally grasp the argumentation and gain the skill of logic and analysis, I think many are struggling just to stay on top of the text.
All this isn't really an answer to the question, but more observations on the challenges of teaching it.
The last point I'd add, is that I'd love to see some inspiration - the kind of hashkafa changing shift that can happen when learning Ramban, Kli Yakar, etc., as well as a "ולכן " - a practical application about how this is going to impact their life and change them as a person.
