If you make reactions automatic they are not reactions anymore. I mean, It is ok if you make attacks of oportunity or counterspell automatic, they already made it in NWN, P:k, etc. But you only have one reaction per turn, and if they do not allow you to choose if you want to use it or not, or against whom you want to use it (maybe you want to block with your fighter or use cutting words with your bard against the bashing of the ogre, not against the goblin with the dagger. Maybe you want to protect your squishy caster instead of your full-armored fighter; or even do nothing at all. You cannot do it if the game makes automatic choices for you). Also, not all reactions are easy as counterspells or attacks of oportunity.
I meant that reactions can have a system like FF12's Gamibits kinda. So you would get to create triggers that your characters react to. As for cutting words you could take "always ask" if you wish to use it, or you might want to have "ask to use if *insert characters* is targeted" in order to aviod using it on tanks. Or if you wish to have quicker gameplay "use if *insert characters* is targeted" . It will be intresting to see what larian has come up with.