Yesterday I attended the YU-SOY book sale on Alumni Day. One of my goals was to purchase R Hayyim Volozhiner's work on Avoth titled "Ruach Hayyim"
In usual cosmic irony the computer had it located in the Mussar-Qabbalah section, but it was only to be found in the Mishnayoth section. Go Figure! ;-)
Anyway its haqdamah outlines the proper Mithnagduth approach to Qabbalah
Though many of Rabbeinu's words are founded upon the Zohar and the writings of the Arizal
[Nevertheless] He would not preach the esoteric in public, [Rather] the words in "Ruach Hayyim" are explained in an idiom fit for all, and many of them [serve] as an introduction to the work "Nefesh haHayyim"
As we see again:
Mithnagdim DO Qabbalah,
And they do it ONLY as Nistar in private and not in public.
IMHO this is the proper balance in handling the esoteric, the Centrist approach. IE The "Arba nichnas l'fardes" approach; The Maimonidean approach to teaching Maaseh Breishith and Maaseh Merkavah.