Not sure what the TM6 form was like in October 2017, newalaan2, but if it was the same long (19cm) two forms used back in October/November 2016, when I arrived at Suvarnabhumi Airport, and which had not changed for years, then the TM6 had indeed changed when I arrived in Bangkok on Saturday, 13 January 2018.
When given the form on the airplane, I always keep a pen and a piece of paper in my cargo pants pockets, with my passport number, flight number and any other details I cannot immediately remember, to enable me to quickly complete the form.
I am happy to say the departure card portion, which is retained in your passport, is now only 9cm long and can be easily stapled to a page in your passport without having to fold it.