How do I go about creating the following table in tikz?
\documentclass[11pt]{article}
\usepackage{multirow}
\usepackage{geometry}
\usepackage{tabularx}
\usepackage{booktabs}
\usepackage{ragged2e}
\begin{document}
\begin{table}[ht]
\centering
\begin{tabularx}{\textwidth}{cc>{\RaggedRight\arraybackslash}X>{\RaggedRight\arraybackslash}X}
\toprule
\multirow{6}{*}{Outer index 1} & Inner index 1.1 & Text data placeholder. May be long enough that it needs to be wrapped. & Text data placeholder. May be long enough that it needs to be wrapped.\\
& Inner index 1.2 & Text data placeholder. May be long enough that it needs to be wrapped. & Text data placeholder. May be long enough that it needs to be wrapped.\\
\midrule
\multirow{6}{*}{Outer index 2} & Inner index 2.1 & Text data placeholder. May be long enough that it needs to be wrapped. & Text data placeholder. May be long enough that it needs to be wrapped.\\
& Inner index 2.2 & Text data placeholder. May be long enough that it needs to be wrapped. & Text data placeholder. May be long enough that it needs to be wrapped.\\
\midrule
\multirow{16}{*}{Outer index 3} & Inner index 3.1 & Text data placeholder. May be long enough that it needs to be wrapped. & Text data placeholder. May be long enough that it needs to be wrapped.\\
&Inner index 3.2 & \multicolumn{2}{>{\hsize=\dimexpr2\hsize+2\tabcolsep+\arrayrulewidth\relax\RaggedRight\arraybackslash}X}{Text data placeholder. May be long enough that it needs to be wrapped. Text data placeholder. May be long enough that it needs to be wrapped.}\\
&Inner index 3.3 & \multicolumn{2}{>{\hsize=\dimexpr2\hsize+2\tabcolsep+\arrayrulewidth\relax\RaggedRight\arraybackslash}X}{ Text data placeholder. May be long enough that it needs to be wrapped. Text data placeholder. May be long enough that it needs to be wrapped.}\\
&Inner index 3.4 & \multicolumn{2}{>{\hsize=\dimexpr2\hsize+2\tabcolsep+\arrayrulewidth\relax\RaggedRight\arraybackslash}X}{ Text data placeholder. May be long enough that it needs to be wrapped. Text data placeholder. May be long enough that it needs to be wrapped.}\\
&Inner index 3.5 & \multicolumn{2}{>{\hsize=\dimexpr2\hsize+2\tabcolsep+\arrayrulewidth\relax\RaggedRight\arraybackslash}X}{ Text data placeholder. May be long enough that it needs to be wrapped. Text data placeholder. May be long enough that it needs to be wrapped.}\\
&Inner index 3.6 & \multicolumn{2}{>{\hsize=\dimexpr2\hsize+2\tabcolsep+\arrayrulewidth\relax\RaggedRight\arraybackslash}X}{ Text data placeholder. May be long enough that it needs to be wrapped. Text data placeholder. May be long enough that it needs to be wrapped.}\\
\bottomrule
\end{tabularx}
\end{table}
\end{document}


makecellwill make it much more straightforward to vertically center the stuff. Of course, there are things for which you may want to use TikZ but IMHO not for that. – Mar 20 '19 at 18:34