This is an old (and still held) view of mine (not necessarily about GR 150 per se), but decreasing the gap between the max GR that solo vs 4 man group players can achieve. Historically, this gap has been in the 10-15 GR range. In the old forum, I suggested that solo GRs are rescaled in terms of monster HP to make it so that the top solo players could clear a similar GR to the 4 man team.
In terms of balance, the mantra of “Only buff, never nerf” is just an opinion like “Use both nerfs and buffs”. The truth is the developers have decided on the latter. I support their decision.
When I read this, I realized that it would be exceptionally unlikely that I could make a case that would change his belief of “Only buff, never nerf.”
If I owned 7 cars and one was obviously broken, I would fix it. I would not break the other 6 cars to match the “obviously broken” one. He is entitled to his opinion and so am I on this issue. It is a matter of taste. Some people like chocolate some people don’t.