A better suggestion would be to rework rerolls and how rerolling legendaries work, not go back on something the staff team are trying to improve on. This suggestion has got to be the most selfish idea i've ever seen.
Nikola isn't supposed to be used as a free reroll. Heck, now that newer legendaries respawn in the same area, I hope they implement that to all the older legendary Pokemon and make Nikola a regular boss.