We wouldn't even be having this conversation if they had decent fights for low level characters because no one would feel the need to long rest often if the fights were more appropriate.
From the way you descibe it ... it seems more like that combats will be exactly the same, only enemies would look different. O_o
How wpuld that change the situation?
I mean ypu said it yourself those arent really intellect devourers ... in fact they are basically that giant rats with different skin to fit better to story tone.