Weakn1.4 Resist0.714 Stab1.2
Answers
That's quite a huge change here. IMO, they should increase the SE bonus ONLY for defenders (and up to 2x), meaning that poorly choiced attackers would be punished. By this way, dragonite would not anymore be a generic attacker.
Here I'm afraid it will be easier than ever for attackers to pull down a gym. That was really not necessary because attackers already had the (huge) advantage of knowing their opponents...
We now have less defenders in total. A probable 6 vs. 6 format will allow optimal attacker choice. Some defenders will be weakened from lack of motivation. Now the increase of supereffectivity. Together this will make gym defense paper thin.
Which is why I expect they will bolster the defenders in some way. An increase of the current stamina bonus or an additional DEF bonus. Shorter time penalty. Or a chance for the defender to dodge.
Glad I had a habit of keeping mons with various moves, even if not STAB. Soon they will be more effective as attackers into specific types.
e.g. one Arcanine with Bite, the other with Fire Fang.
Against a neutral defender: Bite * 1, Fang * 1.2
Against a defender weak to fire: Bite * 1, Fang * 1.68
Against a defender weak to dark: Bite * 1.4, Fang * 1.2
(this last one used to be Bite * 1.25, Fang * 1.25)