In Argentina, at least, we use "Te extraño" a lot. It's a regular phrase between lovers, friends, parents and kids, etc. "Extrañar" is a common verb, much like "amar" or "querer", in relationships.
"Me hacés falta" (in Argentina, with an accent), on the other hand, is limited to love relationships, more intimate as you say, and more like "I need you" than "I miss you". (Funny, but in Italian, as far as I know -which is not very far, btw, haha- the phrase for "I miss you" is "Mi sei mancata/o" = me haces falta; I mean I think there's no other option...) Of course you can say "me hace falta dormir más", or "me hace falta un lápiz" (= I need) and there's no love relationship involved! And you can also say "Extraño mi cama" (when you're sleeping some place else) or "Extraño esos días..." (no love meant, but just nostalgic...).
There's another use of "extrañar"...
"Me extraña que no entiendas, Vicente." (= I'm amazed) (hahaha... sorry
!)
But you understand me, because we're not "extraños" (= strangers)
Good enough explanation?