Wouldnt be better just to get rid of spawn bug?
I wouldnt doubt its already fixed we're still just waiting for update.
About the suggestion: There should still be town preview, why wouldn't you be able to see guys standing at an entrance to town? Other then keeping that, yeah, it's a good suggestion if implemented right, from what i heard it was implemented pretty badly the first time, which is why people burned it at stake at the mention of it till now.
Now that we know the goals of this suggestion, lets think about all the things that could go wrong, and ways to possibly fix them.
Such as how this will keep mercenaries from autoattacking? All you gotta do is move once spawned in and "PEW PEW" it will only give most players a +1 second...