I thought it was a strange change too, especially as FFXI had the complete opposite - if you were running in heavy armour you ended up sounding like Steiner from FFIX with his humorously exaggerated armour clanking as he ran. Maybe it was considered too annoying and thus SE decided to tone it down in FFXIV. Which is a shame, as I actually liked the clanking of my armour in FFXI (WAR was one of my mains and I normally wore heavy armour like the Adaman/Koenig set accordingly), and miss it here.