Then I guess an Undertale LP isn't for you. The Temmie armor doesn't help that much honestly, I've noticed that he doesn't take much less damage than I did(without it) and the only upside is that he occasionally heals(which the apron also does). The only enemies that are supposed to be a threat are most bosses and it still applies there.
The only way they could make the battles more challenging is if they carried less health items but why bother when the point of the battles isn't about survival? I think you'd be way better off watching a genocide run of Undertale rather than a pacifist run.
An example then, Undyne attacks take off 3 HP majority of the time. Temmie armor? 1 HP.
That was the point where I just sighed while watching Matt tank damage and avoiding few attacks. The final few bosses are the only thing that challenge him due to Temmie armor only detracting about 1-2 points of damage making it 3 on hits instead of 4-5. I don't mean they shouldn't use health items either. I just mean they could tank damage in the longer bouts near the end of the Undynes battle without little work needed to live. A longer attack pattern wouldn't mean much as he could just eat most of it and be fine at the end. Maybe others dumped the gameplay care by the wayside since people seem to be devouring a lot of Undetale LPs while I'm not, but I was hoping Matt would be a little more engaged to try and dodge things than not at all.
Edit- And after fully watching Undertale Part 12, man, are their reactions super tempered. I would think a Matt and Liam LP would bring more hype, but I guess that's a Woolie and Liam thing now.