Here is a suggestion to improve PDF Architect in future upgrades:
In the "Merge Files" portion of the program where it allows re-arrangement of files, why not add a "Drag & Drop" method of moving files to the place where you want it to be.
As an example, if there are over 100 files to be merged, and I have 5 or 10 files to move, using the "up and down arrows" method to re-arrange is very time consuming.
thank you for the suggestion, I will pass it on to the PDF Architect team.
I can't say if or when this will make it into PDF Architect, but you could have a look at PDFCreator Online as an alternative, as you can drag&drop files there in order to change the order when merging.
It's free, doesn't require any login or installation and works from any browser.