I will be leveling Mining/Engineering in sharded Durotar and I will be hitting level 13 with a mix of Tirisfall and Durotar quests before i even enter barrens. If Barrens in sharded I will do the same with mining. Basically i am going to milk sharding to all new levels by camping silver veins and jumping shards. If Blizzard is going to have the awful system in I might as well just abuse it.
There is more resources spawning in total.
Each shard will have spawns, and with the more shards there will be more spawns. Technically there will be more mats and nodes. Will it have a huge economic impact? No. If there was sharding in 40+ zones would it? Yes. Mithril, Thorium, and Arcane Crystals + Plaguebloom, Gromsblood, and the Brack Rotus.
As i said above. I am going to abuse the hell out of it to get out of tin.