Fair enough, some difference of opinion, but appears to me pretty similar.

Too many parens is as bad as too few. I use parens on most sub calls with some Perl bareword exceptions. print, join and some of those things... I always use paren's when calling my own subs.

Actually as you can see, we have the same philosophy of coding:
1. check args...first thing...
2. open files..very early in processing..
3. do processing

For user errors, I find for my users (who aren't that sophisticated), my error message is enough in the "die", "can't find APP X's config file $path/.ini" or similar is enough. If they can't figure it out from that, then I want to know the line number. The $! info is noise to them. That is "in-between info" and I put it there for more sophisticated users. So I do put it in there.

On open's, well fair enough. 3 parms is "better", but I can't say that with authenticated users 2 parms like I did is bad. But few extra characters is no problem.