Summoned monsters were never a big deal. They were always super weak for combat and unless you could get lots of them on the field they were at best flankers. While fairly versatile they were by no means overpowered. Summoners are fairly useful in that their summoned monsters last a long time, but they are still pitiful combatants. In addition the extra actions (especially if a small army was summoned) could take a while but I never encountered a player that cared.
My group and I played this section last weekend.
Overall the game didn't exccite anyone and we aren't playing PF2 anymore. We are adding a lot of the Pathfinder unchained optional rules such as the three actions. In fact unchained has many of the PF2 ideas a the three action system ready to Port to pf1.
With the duration reduced wild shape is almost useless.
So far pf2 the following is more fun....
I wasn't thinking all of them at the same time, just some.
The frenzy is similar to the standard attack array that I postulated so that is what I was thinking.
The game now would have bite/bite/bite or whatever instead. Definitely worse