That's why awk is so often used with sed, as awk is great for the first part while sed is very good for the second. For example:

    echo $BUNCH_OF_TEXT | awk '/amazing/ {print $1, $3}' | sed 's/amazing/mildly interesting/'

| awk 'sub(/annoyingly clunky/, "pretty easy")'

a lot of people pipe to sed but you don't need to. you can do regex subs right in awk. see sub and gsub.

       sub(r, t, s)
              substitutes  t  for the first occurrence of the regular expression r in the string s.  If s is
              not given, $0 is used.

       gsub   same as sub except that all occurrences of the regular expression are replaced; sub  and  gsub
              return the number of replacements.

(this is awk from osx, which i think is nawk)