One of the benefits of context minimals is that you can install multiple versions in parallel, which allows the user to update frequently without the risk of breaking something for long-term projects. Specifically, you can keep a "frozen" version of context for long-term projects and install a newer version in parallel for newer projects.
For sure! My environment looks as follows:
export CONTEXT_HOME=/opt/context
export PATH="$PATH:...:$CONTEXT_HOME/tex/texmf-linux-64/bin:..."
The /opt/context directory is a symbolic link, which eases switching between versions: I seldom have to change the environment variables settings.
So, your suggestions should be included as a separate script and not as part of the default. Then there is the question of providing an uninstall script as well...
Using a ConTeXt-specific environment variable (e.g., LMTX_HOME) would make uninstalling a matter of removing it from the PATH and registry (on Windows, anyway). Here are the current instructions: