Very much appreciate the question. Honestly not sure about the year in tennis.
Think it was a decent year for the WTA. Quite a few breakthroughs and new players becoming popular and gaining fans e.g. Kerber, Puig, Pliskova. Kerber becoming number 1 has been great and ushers in a new future for tennis. Good to see variety in slam winners with Kerber winning 2 and stunning everyone with the year she's had, Muguruza at the French (but doing nothing much since then) and Serena at Wimbledon showing she still has what it takes. We've seen a big decline in former top 10 players whether injury or form slump e.g. Ivanovic, Jankovic, Bencic, Safarova, Makarova, Bouchard, Errani, Petkovic and Wozniacki (has since turned it around). Had quite a few comebacks such as; Stosur and Venus back to a slam SF, Cibulkova, Kuznetsova back to the top 10. Had great dramatic storylines too; from Sharapova testing positive to a banned substance to Azarenka having a great start to the year and then shocking everyone by getting pregnant. WTA in 2016 had it all.
Can't say the same for the ATP which has been horrendously boring in my opinion. Same old stuff really. Murray v Novak slam finals, Novak dominating the Masters. Occasional upset like at Wimbledon or Rio but both times the end result was the number 2 Murray picking up the prize and not someone else breaking through.. Unfortunate year with injuries for Fed and Nadal. Good to see DelPo return, have Thiem breakthrough and Stan winning a slam (but then falling back into oblivion..). Same old Kyrgios drama and #nextgen players not winning Masters or slams.