LaTeX style or macro for detailed response to referee report

Given the lack of pointers to anything pre-existing, I ended up with the following (and rather simplistic) solution, at least for now:

\newcommand{\pointRaised}[2]{\medskip \hrule \noindent 
               \textsl{{\fontseries{b}\selectfont #1}: #2}} 
\newcommand{\reply}{\noindent \textbf{Reply}:\ }       

The \pointRaised macro takes two arguments. The first is the enumeration and/or location of the issue. This will be set bold. The remainder is the what I chose to quote from the issue raised. This will be set in slanted. The whole block is separated by some vertically space and a horizontal rule.

The \reply simply starts with a bold token followed by the comment.

For insert comments about the text modifications in a LaTeX file according to referee questions, a good and easy option could be make a version with the todonotes package activated. Small comments can be made at margin and big comments might be placed in line. For example:

\documentclass{article}
\usepackage{lipsum}
\usepackage{todonotes}
\title{A more clever title
\todo{Modified according to referee}}
\author{The author}
\begin{document}
\maketitle
\begin{abstract}
\todo[inline,color=green!50]
{Abstract changed to adapt to format indicated in
guidelines to authors. Text has beeen changed to 
reflect the update of Section 2 and Discussion.}
\lipsum[1] 
\end{abstract}
\section{Introduction}
Really et al. (2010) 
\todo[color=blue!40]{Added citation} 
said some important suff.\lipsum[2]
\lipsum[3]
\end{document}

For a letter with questions & answers, this is essentially the same text structure of a exam, so you can use the exam document class. An example:

\documentclass[answers,12pt]{exam}
\usepackage{xcolor}
\definecolor{SolutionColor}{rgb}{0.1,0.3,1}
\usepackage{lipsum}

\renewcommand{\thequestion}{\alph{question} }
\renewcommand\questionlabel{\llap{\thequestion)}}

%\pointsinrightmargin
%\boxedpoints
\unframedsolutions
\shadedsolutions
\definecolor{SolutionColor}{rgb}{0.9,0.9,1}
\renewcommand{\solutiontitle}{}

\begin{document}


Dear Editor in Chief, \bigskip

Please read below our answer about the \numquestions{}
questions made by  both refereees. I hope that you agree
wih all our comments. \bigskip

Best regards,\bigskip

The author

\begin{questions}
\question Spell foo as bar
\begin{solution}
 We opted to follow the ABC style of ... 
\end{solution}
\question  Include reference to Really, Important and Stuff (2010)
\begin{solution}
Section 2 has been updated and the discussion ... 
\end{solution}
\end{questions}

\end{document}

There is a new template for a beautiful authors response to reviewers, that is

1. easy to write, and
2. easy to read.

The content can be written like this:

\section{Reviewer 1}
\subsection{Page 4 Line 12}
\RC Lengthy paragraph about something
\AR I do not agree.
\begin{quote}
Excerpt from the text with latexdiff-flavoured text changes.
\end{quote}

Or alternatively, in Markdown:

# Reviewer 1
## Page 4 Line 12
\RC Lengthy paragraph about something
\AR I do not agree.
> Excerpt from the text with latexdiff-flavoured text changes.

And looks like this: