This...

[Moontide]

If you turn the "easy&fastXP" into harderXP you might make people who like challange happy, but those who liked it the easy way not but if you change another content that not used a lot into (or make a new one) a "challange that give good xp" both will be happy.

While I understand that quite a few would like this approach, I don't really like it. It wouldn't tackle the problem of gear/consumables irrelevance and thus indirectly the irrelevance of DoL/DoH. There needs to be a fair risk versus reward balance to not make one play style undermine the relevance of every other one. "Challenge for the sake of challenge" isn't a very good way to go IMO.