I don't think we can talk about increased difficulties for runs such as Nemere and Razador at least, until we have more of the playerbase able to actually do such runs. There's not many new names I see doing Nemere, even though the run is now last patch content.
However, I'm all up for creating easier difficulties (obviously, with reduced rewards) of previous chapters' major runs - obviously not talking about Naaga, Baroness, DT, but about Nemere, Razador, Earth, maybe Azrael as well (although I wouldn't include it in the difficult categories run).
Thing is, as mentioned by someone on the forums, the great majority of players will not touch Nemere or Nemere items on this server. The same goes for training Dragon's Claw and Heart. But now, since we're in a new chapter, maybe it's time to look into options that make old content easier or at least options that create lower difficulties with lower rewards for old content, maybe with additional restrictions, that would incentivize even the casual players to build some equipment to do those runs.
I'm speaking from the perspective of one of those casual players, so take my take with a grain of salt. Would I love to do Nemere? Of course. Do I have the time to get there? Probably not. Would I ... I don't know ... pay double a key price and have to do 3-4 as many runs to get the results of 1 Normal difficulty run? Honestly, I probably would - more content for me, less boredom, more fun.
But, tl;dr, I don't think the server is in a state where we can talk about bringing more challenges to high-level, end-game people. If we want to take into account longevity and long-term prosperity, we have to look into solutions to make it at least 20-30% easier for players to advance through what is now considered last-chapter content, IMO.