Basic sutures don't bother me too much in the grand scheme of things. If clean, and, um, antibiotics. That said, it's not like skin sutures do much for the types of wounds that Hawkeye and Black Widow are likely to get. They probably need ligatures, deep sutures, subcutaneous sutures, then skin sutures. Maybe some tendon or muscle repair, which still often break down. Just not some wimpy line of simple interrupteds on the skin. So, thus my twitch. ;)