This plugin does do repeatable content with a little bit of work.
However one thing I notice is that it doesn't properly support Tiny MCE textareas - a small bug.
Consider this template:
[accordion_fieldset]
type = fieldset_open
multiple = true
multipleButton = true
[accordion_title]
type=text
blank = true
label = Accordion title
[accordion_intro_text]
type= textarea
label = Accordion title
class= accordion-intro-text
blank = true
[accordion_full_text]
type=textarea
blank = true
htmlEditor = true
cols = 30
rows = 5
tinyMCE = true
[accordion_fieldset]
type = fieldset_close
It adds new content "blocks" correctly however, the of the newly created area is not editable. I think this is due to the ID of the tinyMCE area being duplicated. E.g the toggle editor toggles the original tinyMCE text area not the new one.