The problem with nerfing giratina
A lot of the changes seems specifically geared to nerf giratina. The main one I could see being
This might seem good as giratina was extremely prevalent in ultra. But the problem with this is, its the nature of games like trainer battles is that theres something naturally best suited to the needs. The meta stabilized even with giratina there and was build around it, it wasnt infallible. Things specifically designed to take giratina out will leave a power vacuum, and the next most overpowered pokemon will take its place in about 4 days when we crack the new meta.
This will of course lead to something similar to what happened with giratina happening all over again, one extremely powerful and dominant species, with few counters.
Or who knows maybe these changes didnt really do anything for PvP's meta.
Now here comes the million pokecoin question, what going to fill the gap?
Answers
None of these changes are going to shake Giratina off its throne really. Outrage Snorlax can contest it, that's really about it (well, and Lapras enjoys the Ice fast move buffs but it already countered Giratina). Giratina also got a slight buff itself with Shadow Claw's energy gain being buffed to 8 from 7, making it a more appealing alternative to Dragon Breath.