There are no real plans to remove commandline at short notice. It is just that it is advised to use the parameters.add way as much as possible, because it is better.
Bugreports for quoting, or supporting more scenarios for commandline are no longer accepted, but immediately set as "won't" fix. The deprecated status is more or less meant to reflect that status, so that users don't accidentally make new code with commandline thinking it is supported.
Note that TProcess had quite some changes internally in 3.2.0.