I'm definitely feeling this, and it goes for the boar guard leading to the boss too. I saw that there were some balance tweaks done to make the normal playthrough mode more challenging, but as it stands this feels like too far in the other direction. It feels impossible to deal with the sheer number of enemies, especially when they soak damage and keep pace with healing items, and ESPECIALLY when the special attack misses. Likewise for breaking out of the mind control being able to whiff.
The whole idea of those enemies is that you've gotta deal with them fast, before they call more over. Once it snowballs, you're out of luck, for exactly the reasons outlined. I plan on revisiting a number of things in 1 once 2 is decently underway, but again, from what I remember from playtesting it's entirely possible to clear all of them out without losing by simply using a save to try a few times till you get a good "roll" and locking in each successful battle with a new save. This isn't ideal balance of course, and probably something I'll tweak, but definitely not impossible. The target, especially for the boar guards, is that it be possible, but annoying, thus tempting you toward the other option. But chances are both could be brought down a BIT, and I'll look into that eventually.