wifi.sh is subject to GPL, if you insist on using a tool that does not meet your needs, you are free to modify it to your liking.
Core is a toolkit, and it is the users responsibility which tools to choose and how to use them.
The only automatic invocation of udhcpc could occur when omitting boot code "nodhcp" as a default which may be convenient for some users (it's not convenient for me, but I don't feel that interferes with my freedom a simple mechanism to deactivate it is provided).