Actually, looking at the maps more, I think the 5e map is probably closest to the 1e map, which lacks any roads connecting Baldur's Gate to the Trade Way via the Fields of the Dead. The 2e map has roads that peter out after a while, while the 3e and 4e maps have a road that goes all the way through and connects with the Trade Way south of Dragonspear Castle.
Anyway, I seem to recall having a discussion about which of the older edition maps Mike Schley based the 5e map on way back when the SCAG first came out - so this isn't exactly news.