I am not really convinced that someone should be able to completely block a 10ft passage on their own. Although when rules for longer weapons come out we might see something on that front.
Against a single opponent, this in fact should be easy to achieve (where 5E rules make it hard by default, and require some DM/player fudging). I'd say any width up to ~25' should be blockable, given roughly even speeds, and a 15' starting distance. Not even 4E's generous allocation of an AoO slot versus each enemy can help with that, though.
Against more than one opponent, well it starts to depend on lots of things - the relative powers of the combatants, how mindful those rushing past are that they might be the "unlucky one" that takes a fatal blow so that the group could get past, and whether that kind of scene even counts as fantasy combat in the eyes of the players.
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