\documentclass{article}
\usepackage{amsmath}
\makeatletter
\renewcommand*\env@matrix[1][\arraystretch]{%
	\edef\arraystretch{#1}%
	\hskip -\arraycolsep
	\let\@ifnextchar\new@ifnextchar
	\array{*\c@MaxMatrixCols c}}
\makeatother
\begin{document}
	\[
	\begin{pmatrix}
	1 & 0 \\
	0 & 1
	\end{pmatrix}
	=
	\begin{pmatrix}[1.5]
	1 & 0 \\
	0 & 1
	\end{pmatrix}
	\]
\end{document}