Interesting. I felt that 4e halflings and gnomes had very distinct visual identities - you could always tell one from a human or an elf at a glance, with or without a size reference. Though I suppose it could be a little trickier to tell with Halflings, and in both cases proportions were not the indicator. So I’ll revise my statement: Halflings and Gnomes need to be easily discernible from humans and elves with or without a size reference. Proportions are one way to achieve this, but not the only way.
Aside from the bit of square forehead, I was mostly referring to them being build like normal humans, just smaller. As opposed to the 5E halflings which seem to have a physical build closer to that of a person with dwarfism.
Examples:
Gnomes aren't really that bad. 4E definitely had a more "natural human" design to them, but Gnomes are proportionate, if short in 5E, they don't suffer from overly-large heads or shrimpy limbs.
That’s understandable. Personally this doesn’t bug me. It’s just not a place where my suspension of disbelief is strained, unless the proportions are real messed up like in 5e. But big heads aren’t generally a problem for me.. But everyone has different thresholds for such things, and I can see why this would bother some folks.
I think in PF it always bugged me a
little. 5E made it bad enough that I don't consider 5E's depiction canon in games I run with halflings (substituting visuals from LOTR, humans, but smaller). So with 5E bringing it to a head for me, now I take more open issue with it elsewhere. C'est la vie.
Peraonally, I’m partial to halflings having big hairy feet and no shoes. I remember thinking it was cool how Khajit and Argonians couldn’t equip footwear in Morrowind, and I always thought that would be a neat feature to give Halflings use in a D&D or Tolkien-esque game that had a sectional armor system.
Now that I agree with. I wish they had kept the digitigrade legs for Khajit and Argonians. I tend to apply it to beast races in D&D games, Dragonborn have this problem for example.
But I think 5E did a good job of differentiating the humanoids by a cultural appearance (clothing, hairstyles, equipment) which 4E
did not. You can tell a 5E gnome or halfling from a human or elf not because of the size of their head, but because of their clothing and hairstyles. I agree Lidda had the problem of looking just like a "little human" so without reference it was difficult to ID her as a halfling.
EDIT: since I see someone else brought up that point with you, I want to add this is good for a solid visual identity in the
art. It's less applicable to play.