Still early days, folks. There are 3 possibilities :
1. They might not go ahead with this at all.
2. They will go ahead with it, and make it 30 days again.
3. They might change it back to 30 days for some nationalities only.
Anyway, if they make it 30 days again, it is best to apply for a tourist visa. Especially if one plans to stay for 3 months. So, first, one can use the 2 month-stay that the tourist visa enables them, and then get a 1-month extension within Thailand. Of course, the requirements and the difficulty to get the tourist visa changes from Thai embassy/consulate to Thai embassy/consulate.
Sadly, if they do plan to go ahead with this, it is also worth noting that the chances are high that they will also get more strict with the border runs too. Not just border runs of course. I mean, also with folks who try to get consecutive visa exempt stays via air travel.
Times are changing,folks. And, looking like, for worse.