There is a long standing debate surrounding the piyut "מכניסי רחמים" which is said during selichot (words found here). The piyut is addressed to angels and the text aims to elicit the attributes of the angels to assist in teshuva before the days of awe.
The piyut starts like this:
מַכְנִיסֵי רַחֲמִים הַכְנִיסוּ רַחֲמֵינוּ לִפְנֵי בַּעַל הָרַחֲמִים
מַשְׁמִיעֵי תְפִלָּה הַשְׁמִיעוּ תְפִלָּתֵנוּ לִפְנֵי שׁוֹמֵעַ תְּפִלָּה
מַשְׁמִיעֵי צְעָקָה הַשְׁמִיעוּ צַעֲקָתֵנוּ לִפְנֵי שׁוֹמֵעַ צְעָקָה
מַכְנִיסֵי דִּמְעָה הַכְנִיסוּ דִמְעוֹתֵינוּ לִפְנֵי מֶלֶךְ מִתְרַצֶּה בִּדְמָעוֹת
In brief, the Rambam's 13 principles says that we should only be praying to God*. The Rambam's basis for this is a Yerushalmi (תלמוד ירושלמי, מסכת ברכות, פרק ט', הלכה א') i.e. that all prayers should be directed to God, not the angels.
The piyut first appeared from Rav Amram Gaon's (9th century) siddur, who (it seems) did not oppose this. It also appeared in the Shibbolei Leket (13th century) and Rav Shreira Gaon (11th century) who considered it permissible. The Maharal and the Chatam Sofer were ostensibly against the recitation of מכניסי רחמים and Iggrot Moshe and the Tzitz Eliezer bring arguments against the recitation, but were seemingly indecisive (see here).
Are there any poskim who were more decisive against reciting this piyut? For those against it: what was their reason and how do they understand Rav Amram Gaon (and others) who allowed the piyut to be said in the first place?
NB: If someone has examples (or personal experience) of current synagogues, Rabbanim or Yeshivot that have a stance on this issue it would be appreciated as a comment (or part of an answer).
*I'm using this Rambam as an example, I know there are those who disagree with the codification of the ikkarim in the way that he did.