Right now, there’s a pretty big discrepancy between the amount of points between Master*** and Guildmaster and the rewards you get out of completing that large final stretch.
Your 6th inventory page is unlocked at 17000 points (Master*) which means that in the 83000 points gap between 17000 and 100000 points you do not unlock anything new there.
Looking at this fact, it’s not strange that I as Master*** rank player don’t really feel the need to gain more mission points as all it’d do is unlock more storage space which I’m not even close to needing yet.
Therefore, this suggestion aims to create more late game incentive to cross that massive explorer points gap. An extra inventory slot is always really helpful since it allows you to bring, for example, fam items for multiple pokemon.
I think this reward will be fitting for players at this level since, at this point, they usually have multiple high level pokemon they would like to bring to dungeons along with many useful items.