Skill Endeavour / Council rules have broken math in that with higher dice pools it is actually easier to do supposedly harder (longer) challenges.
Also the sweet spot of these challenges is fairly narrow so you can easily end up with very small odds or virtually automatic odds depending on the swing of d6 modifiers. This is true for 2e in general with using d6 as modifiers but is exaggerated in Skill Endeavours and Councils because they count extra Tengwars.
I'm a big fan of 2e broadly, but I agree with this point. I've noted it in the FAQ/errata thread. I think it is relatively easily fixed by making "required successes" scale up faster than "attempts allowed" (which is what Savage Worlds does with a similar mechanic).
Skill Endeavours/councils: I've found testing a range of scales and often having a scaling approach to successes (extra successes beyond minimum required produce something good) works really well. For example, you save more people from the burning building in a Skill Endeavour, or you get more support from the Council you were entreating with (material resources, a supportive NPC accompanies you, larger rewards, I can grant an extra Patron benefit as if the other party was an additional Patron etc).