I had a similar experience. I tested that mod, using DND numbers, on a fight that was fairly difficult vanilla tactician. It was very easily defeated with the mod active.
Changing the enemy stats is relatively simple though, so you could make a custom tactician with +70% armors instead of +50%.
The issue that prevents me from playing that way is that the relative strengths of physical vs magic aren't preserved. Somehow physical attacks are better after the mod is applied, making an uneven balancing even worse.
I'm too lazy to go through and edit each skill individually so I think I'm going to wait for a bit and see how things shake out. Either until someone else does the grunt work of hand-modifying each skill, and to see what Larian releases in their patch.
