the question it boils down to is this: is it a goal of tinycore to have extensions that work out of the box? if yes, then they need to have a way to integrate with the shared aspects of the system at the time of install and /etc/skel and ~/.aliases are shared resources.
if I install extension X which needs a default config file in each users' home directory to run, then that extension needs to write in /etc/skel (or in /usr/local/etc/skel and make adduser a wrapper that uses that directory), and even write to existing homes at the time of install (I see how that could be considered too intrusive though, especially when /home is persistent but you want to try out some extensions which don't have a way to ask you to cleanup up after themselves).
now ~/.aliases is definitely a user thing and not a distro thing (think of a portable home directory), while /etc/aliases is the distro thing, and /usr/local/etc/bash/aliases is the extension thing -- as long as there's a separation between the three and extension people know about it, i see no problems. what do you think?