Without belaboring, those who IMHO were less than generous in their dissent - and at times rude and malicious - include:
• The Ra'avad on Rambam's Mishneh Torah
• The Re'ah on Torat Habayyit
• The entire anti-Maimonidean movement in the 12th and 13th centuries. An episode of mega-embarrassment
Let's let those go and think positive!
Can we find respectful debate and dissent?
YES we can! In preparing a series on Reshut haRabbim and the issue of 600,000
[600K] I found that the Beth Yosef outlines both schools in a fair-minded and balanced way. Despite his Sephardic Background, he reports quite objectively how the schools hold and how-where they differ.
In the Ashkenazic Tradition, 3 Classic supplementary texts were written that embody respectful dissent, or simply complementary information that mitigate the simple read of the text.
Perhaps the finest Gentleman of that Genre was the Rema. His respectful dissent in his Hagahot are not only lessons showing how Ashkenazim disagreed on point, but he accomplished Two tangential accomplishments
1. Rema made the SA an almost universally accepted text. [Not so for Teimanim, but quite so for both Ashkenazim and Sephardim]. [Also note R Mordechai Eliyahu did much the same for the Kitzur SA]. Rema's alternative might have been to either "bash" the Mechabeir, or to author a competing text. He chose not to. [While his Talmid the Levush did that exactly]
2. Second, he acted like his Namesake Moshe and taught us anivut. He made no claims to being a superior poseiq, only a preserver of a Tradition that was being short-changed. And his manner was done with elegance and class in terms of his respectfulness.
The second respectful dissenter is going back in History to the Maharam miRothenburg and his student the Hagahot Maimoniyyot.
The Maharam was enamored with the Rambam's Mishneh Torah's clarity and organization, and so he latched onto to the bandwagon by commissioning his student - the Hagahot Maimonoiyyit - to produce an Ashkenaz-friendly supplement. The Hagahot here did not catch on in big way as did the Rema's Hagahot several centuries later. Nevertheless a path was made towards both admiring Sephardic codes w/o trampling Ashkenazic sheetot.
NB: just as the Darchei Moshe on the Tur was short-shifted into a "kitzur" apparently the Hagahot M suffered a similar fate
The Darchei Moshe is being restored in the new editions of the Tur and the Hagahot Constantine are now in the back of the Frankel edition of the Rambam.
The least obvious is Tosafot. This deserves more than a sound-byte, but to a great extent, Tosafot finessed a reconciliation between the Bavli and Early Minhag Ashkenaz in such a way that made the Bavli the premier text of TSBP and made it more palatable to Observant Jews whose tradition was at times in conflict with the text.
We primarily covered 3 texts:
And their corresponding respectful "hagahot"
The Rif and beyond