It's quite possible to craft, improve and enchant items that make the game too easy even on master setting, especially when you add in the perks and things like enchanted items for smithing and Blacksmith's Elixir when improving your armor. With my previous character I decided to see how high an armor rating I could get when her light armor, and ended up with one well over 900, not counting the ebonyflesh spell (and that character is at 95 with Alteration). Seems a bit silly, considering the base armor rating for a light Dragonskin armor suit with the shield is around 100. I'm debating how far I should go with that with my latest character. For starters, this time I'm playing without a helmet, although my character does get an enchanted hood that boosts her magicka and flesh spells, and can only use a shield in tough, close combat fights or to block arrows from a good range opponent. Otherwise she has to take the blows and keep her hand free for magic or potions. Currently, she only has the hood and a low-level enchanted ring, but I think I may limit her to just two, maybe three enchanted item for when in combat--maybe make up a "conflicting enchantment" rule for my character where if you use too many enchanted items at once, they start having negative interactions with each other, forcing you to limit how many you can use. I am considering dropping gauntlets too.
I've been toggling between adept and expert with my current character who's still below level 20. I'm shying away from master because I do not want Ancient Dragons swopping down on me before my character can handle them without a very extended fight, but expect to play at master level after a few more levels. But at these settings, she's had a couple of close calls, has intentionally avoided certain tougher opportunities for battle and once fled a wispmother that was totally kicking her ass, which certainly adds variety to the game. But I'm trying not to get her killed (or get her followers killed), although I am not committing myself to a dead-is-dead rule. There are some specific opponents and situations that are genuinely hard, and it's good that within the game you don't have to endure such difficult fights all the time. But I agree the game has a problem with keeping it challenging with all the improvements and perks available to you.