I respect Nikola Aracic from Intuitive Tennis much more than Mouratoglou. At least Aracic was a legitimately high level player. The only playing result I can find for Mouratoglou on the ITF site is a first round loss in the qualifying of a Futures event 23 years ago. Felix from the Tennis Brothers Youtube site is already more successful as a tennis player than Mouratoglou.
Now, I know that it doesn't always take being a world class player to become a world class coach. There are countless parents and teaching pros around the world that have coached kids into the pro ranks. Rune no doubt had several coaches like this. However, at this point, Rune has reached the top 10 and needs someone who can help him get up to the next level, which is top 5 and contending for Slams. I did a bit of research on Mouratoglou and this is his coaching client list:
Marcos Baghdatis (1999–2006)
Anastasia Pavlyuchenkova (2007–2009)
Aravane Rezaï (2009–2010)
Yanina Wickmayer (2009–2012)
Laura Robson (2010–2011)
Jérémy Chardy (2012)
Grigor Dimitrov (2012)
Serena Williams (2012–2022)
Stefanos Tsitsipas (2018–2021)
Coco Gauff (2018–2021)
Simona Halep (2022–)
Holger Rune (2022–)
Of those players, I think Baghdatis is the only one that came to him as a young junior and made it into the top 20 under his tutelage. The rest seem to have come to him with their games already baked, and they just seemed to tread water while he was their coach. Again, Serena is the only person that won a Slam with him as her coach, but she was already a multi-time Slam champion when she got into his clutches.
Maybe I am not being fair, but Mouratoglou seems more like a consummate self-promoter than a great coach. I'd kind of put him in the same category as Nick Bollettieri in that most of the hard work is done by anonymous underling teaching pros within his academy. But at least Nick basically invented the academy industry and lucked out by having a huge group of talented players in the 80s and early 90s, and he had several kids go from talented junior to Slam champion (unlike Mouratoglou).