Now I don't remember exactly who proposed this one (it came up during a lengthy forum discussion) but I like this solution a lot so here it goes:
House Rule : When an action card has recharge counters on it, you may try the action again. You have to add to the roll as many Misfortune (Black) dice as recharge counters on the card. Use other recharge rules (ie, adding and removing recharge counters) as in the core rules.
Reasoning Behind : In RPGs I don't like telling my players "sorry, you cannot do that because the rules say so"; I find this reasoning too gamey. One Golden Rule in RPGs has been always to give players a chance (see, for example, page 192 of the WFRP2 rulebook) and this is one of the things that clearly distinguises boardgames from RPGs.
I found it a pity that the core rules force you not to use an action some time after using it once, specially since they have such a nice mechanics (adding White and Black dice) to cope with these situations... Also, after having played D&D4, I have come to dislike very much the concept of "At Will", "Encounter" and "Daily" powers for reasons too numerous to describe here.
I think the above houserule makes more sense. After you try an action once, people around you are more prepared to counter it if you repeat the action immediately, so the difficulty should rise but you should still be able to try again if you want to. Time needed to perform an action should not be an issue here. If you need some extra time to prepare/carry out an action, then you should not be allowed to do anything else (ie, you should be spending your free actions/fatigue tokens for that).