Repairing armor wasn't a challenge. Unless you consider "carrying something with me to click on" a challenge.
As for spellmaking, that's clearly been a huge debate, but you have no clue whether the spell collection is more or less diverse than Oblivion. Because you don't know what spells are available.
It's as much of a challenge as carrying potions to heal, except it was all about repairing the armor, not your health. Or should we remove potions as well? Even if I or YOU don't find it a challenge, apparently quite a few people do, as you can see in the poll. Should we leave them behind because you don't think it's a challenge?
They said that there would be "85 spells", which regardless of how you want to see it is a lower number than Oblivion. We also had removed magic schools and Destruction is now elemental magic, so all points to that direction. And as I said, even if that isn't the case, it doesn't justify removing spellmaking, people enjoy creating, as simple as the system is.