I’d absolutely love more sliders, I still regret for instance they never added a slider to make eyebrows wider (Sims 2, Medieval and Sims 4 have one so I don’t understand why Sims 3 doesn’t). Eyebrows in fact can completely change the appearance of a face so another tip would be: play around with those eyebrow settings. And dare to choose a not so pretty one, they might turn out quite nice on your sim’s face.
http://kobayne.weebly.com/uploads/1/7/3/2/17320944/2198599_orig.png
(this is one I avoided to use for years but I love it for him)(and his son)
https://i.imgur.com/JX8AIC1.png