... should be solved in 1.5.3...
... it has a renewed text engine which is much more powerful and should also be faster...
... thanks to our friends in oman and to khaled!
... which should come out before the end of the month...
for the time being, you could switch all keys on your keyboard, so that you get slower and don't not notice how slow scribus is : - )
(or just type your text in libreoffice and then load it into scribus...)
(and, yes, 24 linked frames might be much for 1.5.2...)
(some 1.5.x versions also have issues with multiple layers)