Personally I don't think interpolation is the solution here.
I think interpolation is mostly useful where it makes a string clearer:

print "Hello " . $name . ".\n";       # not bad
print "Hello ", $name, ".\n";         # hope no-one set $,
print "Hello $name.\n";               # nice and clear

print "Hello " . f($x) . ".\n";   # this is usually what I like
print "Hello ", f($x), ".\n";     # has the advantage of print a list 
+of return values from the function without needing join (which is goo
+d and bad)
print "Hello @{[ f($x) ]}.\n";    # feel free to sit and stare inexper
+ienced Perlers and maintainers
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In the first case interpolation is nice, but in the second a list or concatenation is a little clearer. And anyway the early stages of complimation seperate variables from strings (look using `perl -MO=Deparse foo.pl` if you don't belive me).