I had the anti Duration wording as well but then I realized that tracking is not that huge of an issue.
The card is still in front of you at least until the start of the next turn; if people durations by tapping the card or by putting them into another row, they could do this on the Tavern mat as well. It wouldn't work with my other-than-"at the start of your next turn" Durations, but with the original ones it should work well.
The Attack problem sounds important. I guess it allows the player to go completely destructive. If he buys nothing than Accolading a Witch every turn, it feels like Saboteur - he doesn't do any good for his own deck at all, just harming the other players.
So maaybe it would be better to give it +1 Buy for $3? So you are able to buy a regular card as well?
Accolade (Event) $3
+1 Buy. Choose an Action that you have in play. Put it on your Tavern mat.
(You may play non-Reserve Action cards in your Tavern Mat as if they were in your hand.)