Just thought about one potential change.
While Tibetan tradition is important, maybe the way to incorporate is like for Judaism - to include as half a work in the Old Testament of the Christian Bible. The specific thought I have is to substitute the South Asian Canonical Text List for Nagarjuna's Mulamadhyamakakarika with Tsong Kha Ba's Ocean of Reasoning Commentary to the same work. That way Tibetan tradition would be included.
And this change would have other advantages:
1. Records of the Western Regions dictated by Xuanzhuang, is a geographic work that typically wouldn't be included based on my rule for text inclusion (no geographic texts). This is included because of the lack of histories for India's Golden age. So while it is created in East Asia, the text have have a leg in South Asia. To include Tsong Kha Ba's Commentaries to Nagarjuna would introduce a work in the South Asian list with half a leg in East Asia - so overall balance would still work.
2. This also take out the imbalance once one counts The Awakening of Faith as a separate work from Wonhyo's Commentaries - if one does that, there would be more work included in East Asia (in case you believe The Awakening of Faith is indeed a Chinese rather than an Indian work). Reducing the Tibetan language work would help mitigate this.
3. Proposal to replace Tsong Kha Ba's work with Bi Yuan's 畢沅 Xu Zi Zhi Tong Jian 續資治通鋻("Continuation of the Comprehensive Mirror of Government") which includes the full chronological history of Song and Yuan dynasties. Arguably this is the several hundred years when China was the clear leading area in the world. And this work is also contributed by Zhang Xuecheng 章學誠, whose main work being on historiographical theory I exclude from the Canonical Text list. This also justifies the inclusion of Tarikh-i Naima in the CWANA list - the inclusion of that text was mostly driven by the belief that Turkish has a reasonably important historical tradition that requires a work to represent; and Naima's work covers Ottoman Empire near its height - and Ottoman Empire is one of the 14 (or 15 if one includes the US) most important empires in the world's history. Song, Yuan, Ming and Qing dynasties all belonged to this select group of 14 empires. Qing, like the British -- one can argue that they are too recent to have canonical histories written for them yet. For Ming, its intellectual history would have been included with Ming Ru Xue An. But to include Ottoman and exclude Song and Yuan (especially when the opportunity exist to include both in one work) would not be as excusable.
Thus the changes suggested:
1. South Asian List: Replace Nagarjuna's Mulamadhyamakakarika with the version version with Tsong Kha Ba's Oceaning of Reasoning Commentary.
2. East Asian List: Replace Tsong Kha Ba's Lam Rim Chen Mo 菩提道次第廣論 with Bi Yuan's 畢沅 Xu Zi Zhi Tong Jian 續資治通鋻