There was a write-up someone did on the wiki, probably under the wish list page, as to why a portable smithy was completely unrealistic.
And realism is still a shoddy excuse for denying something when talking about adding features to the game. It's partly the realism thinking that took the game into decline.
An paraphelia like this would be good even if it just meant you'd suffer 5% equipment damage in battle instead of 10% due to the smiths quick repairs before the equipment can suffer further. It doesn't need to be a "fix 20% equipment damage when ever you want to". Heck, if you've stayed in a region for a turn or two without moving maybe the smith would have time to make some extra repairs in the range of 1-5%.
Would something like that make the game better? I think so.
Is it realistic? Who honestly cares?
