Latest issue of the periodical Ha'Mayaan available here.
R' Shlomo Zalman Auerbach's stance on heter mechirah is fully clarified. R' Posen (author of a great book on Targum Onkelos) has a fascinating letter in which he discusses changes in Tefillah,Mendelssohn (note esp. the letter from R' Yonoson Eibschutz in fn. 12). He mentions as an example the correct pronounciation of Geshem, there is quite a useful post on the subject here.
On the issue of fixing the nusach of tefillos, given the difficulties with the nusach that is called Sefard, I am surprised that no effort has been made to fix this. (See ShuT Minchas Eliezer for a fascinating responsa in switching nuschaos)
[Hat tip: Rav Tzair]