tl;dr - Allow abilities in tournament, not items. Winner-lock the abilitie(s) chosen. If NRS publicly states they are NOT seeking to balance the abilities and they are meant to be ridiculous/broken, then we ban them.
I REALLY hope they allow extra specials in tournament and there is some tourney mode that allows them all to be unlocked.. Its just such a great tactical option and, like in every fighting game ever, there will be some characters that just have AWFUL AWFUL MU's vs some others and a properly balanced extra ability system could be really really useful. Not to mention strategy as a whole, letting you really throw off your opponents based on what you pick and how its implemented. Sure, the abilities could make bad MUs worse, but that's fighting games. i cant believe Im about to say this, but.. I feel like we should trust NRS until they show us IN THIS CONTEXT that that isnt a good idea.
Now, this is assuming its balanced and reasonable of course, but just assuming it isnt/cant/wont be, to me, is like saying in MKX you can only play variation-less because one variation might have moves/abilities that are too strong across the cast or too strong vs certain characters. I think the system should be winner-locked like character choice is and assuming the devs OUTRIGHT state that they are seeking to integrate the extra move system in a balanced way, then we should let it in.
Counter picking has been a thing since there have been counters to pick, abilities seem no different than using any option available to give yourself the best chance.