It's a question that might be well asked over at Dharma Wheel - http://www.dharmawheel.net/viewforum.php?f=77
- to hear what Mahayanists have to say about it (after all, this is the "Discovering Theravada" section, so of course Theravada includes the Pali Canon).
I doubt you would find many Mahayanists accepting the Abhidhamma PItaka (the third basket of the Pali Canon) as "the original teaching of the Buddha and is so to be use at least as the foundation for all traditions/schools", but don't take my word it... best ask them.
"Having understood name-and-form, which is a product of prolificity,
And which is the root of all malady within and without,
He is released from bondage to the root of all maladies,
That Such-like-one is truly known as 'the one who has understood'." (Snp 3.6)
"Whether I were to preach in brief, Sāriputta, or whether I were to preach in detail, Sāriputta, or whether I were to preach both in brief or in detail, Sāriputta, rare are those who understand." (A I 333, Sāriputtasutta)