Please improve comment/uncomment ala SciTe

"I would like to comment a line without selecting a character on the same line"

...never used SciTe but the way you describe it, it appears like it can read your mind.
How do you specify which line to comment? In what system anyway? C-style? html? configuration files?
Sounds like you are refering to line comments and not block comments. Though a mind reading block commenter would be awesome.

"I would like to control where the comment character is inserted. (At beginning of line or at caret or start of first word...)"

How? Additional key-combo's? I haven't tried the macro feature yet but maybe it will do what you want.

All these individual modification request make me wonder if it wouldn't be that far-fetched to embed a powerful event-driven scripting language into the editor's core functionality. Could rewrite most of the other functionalities into this script language allowing ultimate customizability without requiring much understanding of the underlying C-code.
Hmhm...

hmm...
No sarcasm here :)

What I was trying to refer to was this: (from the help file in SciTe)

--------------------------------------------------------
These settings are for the comment commands in the
Edit menu and are defined separately for each lexer.
Not all languages support both stream and block
comments.
Block comments are comments that start with a
particular string and continue until the end of line.
The comment.block property sets the string to be
inserted or deleted at the start of the selected lines
when the Block Comment or Uncomment command is
performed. To make this command perform sensibly over
a range of text that already contains comments and
other code, the string can be defined to contain a
character such as '~' that is not used in real comments.
Set comment.block.at.line.start to "1" to place block
comment symbols at the start of the lines, instead of
just before the first non-blank character of the lines.
Stream comments start with a particular string and end
with another particular string and may continue over
line ends. These are defined with comment.stream.start
and comment.stream.end.
Box comments are a form of stream comment that takes
several lines and uses different strings for the
start, end and other lines in the range. These are
defined with comment.box.start, comment.box.middle and
comment.stream.end.

comment.block.lexer
comment.block.at.line.start.lexer
comment.stream.start.lexer
comment.stream.end.lexer
comment.box.start.lexer
comment.box.middle.lexer
comment.box.end.lexer
--------------------------------------------------------

This way I can configure each programming language the way I like. If I'm scripting in javascript maybe I like my line comments to be "//~" and at-line-start and something else for an other language.

Psychic

And also, it would be great to have two separate functions: one for comment and one for uncomment.
Because the actual function takes the negative of the selected lines.
So if we have a block with a comment line at the beginning, like:
// This block does this
Bla-bla

We can select the whole block and de-activate by commenting all of it.

Thank you