It took me hours to get my most used script to work with IMatch 5 and there is a lot of potential to make it even better. I don't know if I have time to convert my other scripts too 
My experience with converting scripts from IM3 to IM5:
If they are not very complex, I can handle to convert such a script.
If a script is VERY complex, I was not able to convert it. But here is to say, complex means also "not very good".
So I wrote a script completely new in IM5 and because I had the old one, I could work with snippets from there and for some problems users helped me here and finally I had a completely new script - and even much! better than the old one.
And surprisingely it took not that long.
And what is true also: some scripts are not more necessary in IM5, simply because it is integrated natively, like the renamer or the relations.