This probably only satisfies points 3 and 4 but read on if you're interested.

The IBM ISPF editor probably has an unparalleled ability to visually edit files - filtering lines included of course.
I still use it when other Windows editors can't cut it or I'm too lazy to code or script something.
For files I regularly change, I also keep edit macros (scripts really - sequences of commands etc.) to run against uploaded files.



This is a free Windows implementation of ISPF.
http://www.spflite.com/

Here's a very small example of the kind of things you can do from the editing interface.
If not enough, you also have the ability to write macros (scripts) using thinbasic code.


x all                           (exclude all lines)
f Timbuktoo all            (find and show all lines with that string - use C'Timbuktu' if case sensitive)
c buktoo buktu all nx   (change buktoo to buktu on all non-excluded lines)
or
c buktoo buktu all x    (make the change on excluded lines - lines containing Timbuktoo are not affected as they are not excluded)

reset                              (show all lines)
c buktu buktoo 100 200   (make this change only between lines 100 and 200)
or
c buktu buktoo .a .b        (make this change between the lines you've labeled as .a and .b)

This is really just a small subset - the full change command documented here.
http://www.spflite.com/HtmlS/CHANGE.html

Besides the change command, there are many other ways to edit a file - much more here.
http://www.spflite.com/HtmlS/Working.html
e.g. Regular Expressions
http://www.spflite.com/HtmlS/RegExLiterals.html
Or picture strings
http://www.spflite.com/HtmlS/PictureLiterals.html


A learning curve for sure and probably a little quirky if you're not used to using commands to change data.
Well, not that strange I guess if you use an editor with a pseudo command line (vi/emacs etc.)

I ran into this exact problem last week with Beyond Compare Pro when looking at changes in a really long make generated command line.
The "solution" is to use the text compare report feature - the lines wrap quite nicely.


With regard to moved blocks of code, it still annoys the heck out of me that BC battles to correctly detect inserted blocks of code that are similar to preceding code.
Quite often, it show the terminating brace (often more) of the unchanged C code as part of the change set - with the same new code showing up as part of the unchanged code.
I see this happing almost every week and no matter how much I futz around with the alignment options, I can't get it to recognize just the piece of new code for what it is.
Drives me nuts, especially as DeltaWalker and KDiff3 have no problem showing the correct change.