I think the sentence is more accurately stated as “I haven’t developed the right heroes to complete the last mission…”
These new class trials are hard, probably the hardest content in the game currently. Someone with ten good heroes will likely fail or burn a pile of items. As you develop deeper benches, you’ll have more tools (heroes) to complete them with more ease. I used one antidote and on small mana pot to finish the Trials of Fortitude today, because I could bring a strong team developed over 20 months of intense play.
As I wrote in the parallel thread the level requirements was hotly debated in beta (not all beta testers are level 30+). When it was first released, you needed to be level 40 to try the last tier. We complained, devs lowered it to 30. So for whatever reason, the devs feel a level restriction is appropriate but the did listen to player feedback.
As noted above, many games include level restrictions. Many RPGs limit what items you use or what quests you can play. E&P has had level restrictions since Day 1.
Personally I would like to see the requirement lowered but not removed. Maybe 25 instead of 30.