Wang was ranked outside of the Top 50 the last time Halep faced her, just last year in Indian Wells. The 27-year-old went on a tear on home soil in China, winning Nanchang and Guangzhou, reaching the final in Hong Kong and Zuhai and the semifinals in Wuhan and Beijing.
"She's more solid and she doesn't miss that much," Halep said. "She's hitting strong, also on the serve. I think she's a better player than last year and she can improve a lot, also."
Halep is now closing in on the world No. 1, which she lost at the end of January when Naomi Osaka won the Australian Open.
"I just found out from my coach I need one more match to be No. 1 again," Halep said. "I think it's pretty much in my head. I'm happy I'm in this position again.
"Every single day that you are No. 1 is a special day."
She'll play the semifinals of the Miami Open for the second time her in career, against either Karolina Pliskova or Marketa Vondrousova.