Avira > All of our ideological enemies have stressed tanach,
Not sure of this argument, they also stress Humash! Should we stop reading it in shul? True, we de-emphasize 10comm for a similar reason. Yes to 1/3 approach that leads to spending most time on Gemorah (where Gemorah means not just Dafim, but ability to reason, etc, while halakha l’maase belongin to 2nd 3rd of Mishna). Still, this means that by 120 you need to finish not just Shas but Tanach also.
You are also right that Tzionim were using Tanach to build up a view of Yiddishkeit different from the accepted Galut mesorah. Are you saying it is a reason to de-emphasize Tanach? How was Nach treated in early yeshivos? I think Netziv in Volozhin had Tanach on the agenda, I don’t know to what degree.