This is going to sound extremely controversial, however I feel that it must be said.
When the Baal Shem Tov founded Hasidism, besides for the change in ideology, there were no changes in minhagim. Although it is unclear, it seems that it was Rabbi Dov Ber of Mezeritch who changed the nussach.
At that time, Orthodox Jews in Poland would follow Minhag Polin, in Germany would follow Minhag Ashkenaz, in Lithuania would follow Minhag Lita, in Hungary would follow Minhag Ungaria (although there were slight differences between the north and south), in Russia, Ukraine, Belarus and Latvia would follow Minhad Reisin, etc.
There is a halochah of Minhag Avoseinu BeYodeinu. When the minhagim were changed by the Chasidim, this was completely against this halochah. However, I do not want to be misunderstood as implying that the Chasidic Rebbes made a mistake. The Chasidic Rebbes obviously knew this halochah but thought that the Nusach of the Arizal was the original Nusach for all Jews in Europe (excluding Spain, Catalonia, Gibraltar and Turkey).
This, of course, had great historical evidence because the Arizal had written out a detailed list of corrections on the Sefardi siddur and gave them to his Sefardi student, Rabbi Chaim Vital, who lived from 1542 to 1620. Rabbi Chaim Vital was given these corrections because there was a huge dilemma amongst Sefardi Jews. After the 1492 expulsion from Spain, the Jews of Spain, who followed Minhag Sefarad, and the Jews of Catalonia, who followed Minhag Catalonia, were mixed together. Fast forward to the time of the Arizal and Rabbi Chaim Vital and you can see that the descendants of the survivors of the expulsion (who remained Jewish) had little or no idea what minhag they are meant to be following, i.e. they did not know whether their ancestors were Sefardim or Catalonim. Therefore, the Arizal wrote these corrections and gave them to Rabbi Chaim Vital, in order for the Sephardi/Cataloni Jews to follow a mash-up of both minhagim.
These corrections were what that the Chasidic Rebbes based their brand new nussach on. The nussach that the Arizal followed. Of course, it is common knowledge that the Arizal was a yekke who would daven in the local Yekkish shul in Tzefas on Shabbos and Yom Tov in order to say Yotzros, as was his mingaim. Of course, the Arizal specifically says that anyone who deviated from their father's nusach of tefillah, their tefillos would not be accepted in heaven. And of course, these corrections were only made for the extreme circumstance of the time - for those Sefardim/Catalonim who didn't know their fathers' nusach of tefillah.
Therefore, it makes perfect and logical sense for the Chasidic Rebbes to change the centuries old minhagim of Europe to the nusach that the Arizal made for the Sefardim and Catalonim.
With all of this in mind, you should definately change your yekkish minhagim that date back to the Rishonim to the Galitzianer Chasidic minhagim that were intended by the Arizal to be used by Sefardim and Catalonim.