FIA president Jean Todt admits that the current Formula 1 engine regulations went "a bit too far" in terms of complexity.
Todt says that F1 has to be a combination of sport and R&D for the manufacturers.
However, he acknowledges that the hybrid V6 rules, which have been in place since 2014, may have focussed too much on the latter direction.
The FIA and F1 have worked together to formulate a revised version of the current engines for 2021, without the complexity of the MGU-H.
"I think we wanted to take as much as we learned from the existing regulations," said Todt. "And to try to make things more simply.
"It's a beautiful piece of art, of technology, but I hear well that it's maybe not what the fans are expecting.
"It's not something that is absolutely needed to have a good championship.
"So I think it's important that we can learn out of it, and propose something which is supposed to be more simple.
"For me motorsport, and I have been saying that every time, is on one side a show, but it is not enough. It has to be also a laboratory.
"A laboratory for the manufacturers, a laboratory for the teams, and a laboratory which can then be profitable on road cars as much as we can. And it is what is happening.
"Saying that, if you think that it has been maybe a bit too far, you must be prepared to go a bit backwards.
"At the end of the day I'm sure that over the years the engine will be even more efficient without MGU-H."
Todt says that the definitive rules are nearly ready, and he hopes that will encourage new suppliers will agree to come into the sport.
"We are progressing quite well on the engine. I mean we are close to respecting the deadline we have to publish the engine regulations for 2021, and I hope that it may create some interest for some new manufacturers.
"There is interest, but between interest and commitment, there's a big difference."