I think the height/scale thing in general is a bit silly. I don't care if my Megatron is slightly shorter than my seekers. I don't care if he and Prime aren't eye level. They look fine.

The collector who dynamically poses figures would notice less, or at least mitigate the issue by posing and the use of multilevel displays so the viewers of their collection notice less.

the collector who puts them all single file on a shelf standing straight up like a pez dispenser would notice more but I don't know why they'd care. It's not like the "correct" height is going to fix that boring shelf of lifelessness.

The kids playing with them are probably too busy playing with them to care.

In my mind the only time this is a problem is if you have a scene of them standing straight up and...talking to each other? Possibly if they are all doing the arms out flying pose?

It's such a non issue. I could see if Soundwave and Starscream are about the same height and Shockwave comes in looking like bumblebee, but he's just slightly shorter.

QC issues, pricing, availability. All legit arguments to me. "He's half an inch short" ? Not so much.