You can probably allow line-breaking within the table-cells themselves.
Besides this you can probably rotate tables that are too wide.
\documentclass{article}
\usepackage{microtype}
\usepackage{graphicx}%
\usepackage[official]{eurosym}
\usepackage{tabularx}
\usepackage{booktabs}
\usepackage{array}
\usepackage{varwidth}
\newsavebox\tablebox
\newcolumntype{L}[1]{%
>{%
\raggedright
\hsize=#1\hsize
\begin{varwidth}[t]{\hsize}%
\narrowragged
\hyphenpenalty=50
\exhyphenpenalty=50
\doublehyphendemerits=50
\let\newline\\%
\arraybackslash
\hspace{0pt}%
\vrule width 0pt height 1.25\ht\strutbox depth 0pt %
}%
X%
<{%
\vrule width 0pt height 0pt depth \dimexpr1.25\ht\strutbox-\ht\strutbox+\dp\strutbox
\end{varwidth}%
}%
}
\newcolumntype{C}[1]{%
>{%
\centering
\hsize=#1\hsize
\begin{varwidth}[t]{\hsize}%
\narrowragged
\hyphenpenalty=50
\exhyphenpenalty=50
\doublehyphendemerits=50
\let\newline\\%
\arraybackslash
\hspace{0pt}%
\vrule width 0pt height 1.25\ht\strutbox depth 0pt %
}%
X%
<{%
\vrule width 0pt height 0pt depth \dimexpr1.25\ht\strutbox-\ht\strutbox+\dp\strutbox
\end{varwidth}%
}%
}
\fboxsep=-\fboxrule
\begin{document}
\noindent text text text text text text text text text\linebreak
\savebox\tablebox{%
\begin{tabularx}{\textwidth}{@{}C{.6}L{1.5}L{1.4}C{0.55}L{.95}@{}}%
\toprule
Veri\-fi\-ca\-tion&Deterministic Versions Comparison&Expected Outcome&True?&Proof\\
\midrule
1 & Current allocation vs. Optimized & Optimized~-- Cheaper allocation & Yes & \euro 411,03M vs. \euro 405,82M \\
2 & Optimized vs. Capacity constrained (no UK-EUR) & Optimized~-- Cheaper allocation & Yes & \euro 405,82M vs. \euro 406,40M \\
3 & Capacity constrained (no UK-EUR) vs. 70\%-30\% volume split by brewery (no UK-EUR) & Capacity constrained (no UK-EUR)~-- Cheaper allocation & Yes & \euro 406,40M vs. \euro 407,05M \\
4 & 70\%-30\% volume split by brewery (no UK-EUR) vs. Sustainable version (no UK-EUR) & Sustainable version (no UK-EUR)~-- Lower transportation costs & Yes & \euro 16,79M vs. \euro 14,40M\\
\bottomrule
\end{tabularx}%
}%
\begin{table}
%\centering
%\rotatebox[origin=c]{0}{%
\begin{minipage}{\wd\tablebox}%
\usebox{\tablebox}%
\caption{Verification of the expected outcomes of the versions of the deterministic model.}%
\end{minipage}%
%}%
\end{table}
\newpage
\noindent text text text text text text text text text\linebreak
\savebox\tablebox{%
\begin{tabularx}{1.25\textwidth}{@{}C{.5}L{1.9}L{1.45}C{0.35}L{.8}@{}}%
\toprule
Veri\-fi\-ca\-tion&Deterministic Versions Comparison&Expected Outcome&True?&Proof\\
\midrule
1 & Current allocation vs. Optimized & Optimized~-- Cheaper allocation & Yes & \euro 411,03M vs. \euro 405,82M \\
2 & Optimized vs. Capacity constrained (no UK-EUR) & Optimized~-- Cheaper allocation & Yes & \euro 405,82M vs. \euro 406,40M \\
3 & Capacity constrained (no UK-EUR) vs. 70\%-30\% volume split by brewery (no UK-EUR) & Capacity constrained (no UK-EUR)~-- Cheaper allocation & Yes & \euro 406,40M vs. \euro 407,05M \\
4 & 70\%-30\% volume split by brewery (no UK-EUR) vs. Sustainable version (no UK-EUR) & Sustainable version (no UK-EUR)~-- Lower transportation costs & Yes & \euro 16,79M vs. \euro 14,40M\\
\bottomrule
\end{tabularx}%
}%
\begin{table}
\centering
\rotatebox[origin=c]{90}{%
\begin{minipage}{\wd\tablebox}%
\usebox{\tablebox}%
\caption{Verification of the expected outcomes of the versions of the deterministic model.}%
\end{minipage}%
}%
\end{table}
\end{document}