Hi!
It's pretty trivial for modern editors nowadays, so I might have missed the option.
If I didn't miss it, I really like to have the option in the editor to REPLACE with keeping case as is.
Example:

declare
l_table_alias varchar2(3) := 'USR';
begin
l_usr_id := -1;
end;

After find and replace "usr" with "col" and ticking the "PRESERVE CASE" option, the result would be:
declare
l_table_alias varchar2(3) := 'COL'; --currently this will be 'col'...
begin
l_col_id := -1;
end;

This is currently not possible. It would require multiple case-sensitive search & replace operations.

I have added this to the list of enhancement requests.