Oblivion wasn't that hard. I pretty much walked through it at the default difficulty with one exception: the first Gate battle where you get swarmed with a bajillion Daedra and your NPC companions prove worthless. After the fact, I was told that gets harder the longer you wait and I did mess around quite a while before doing it. Aside from that, I went with your typical sword & board fighter with some healing magic. Once I started enchanting and spell researching, the game became laughably easy. I never cheated or used mods or glitches.
When I played Skyrim, I went with a pure mage character just for something different. Only wore robes and my only melee weapon was a dagger with a soul trap enchantment on it. I still rolled through at the default setting. I'm not complaining about it and obviously I could have jacked up the difficulty but my point is that you don't need to cheat, hack, mod, glitch etc to find a game pretty easy.
I gotta say that any ES/Fallout game is pretty manageable on normal mode if you have common sense and know how to play a video game. I felt the same way with Mass Effect 1 and 2 on normal mode; I had to ramp them up to the highest respective difficulties to feel challenged (although I admit that Insanity on ME2 was mind-numbingly impossible once or twice).
That's why there are difficulty settings on these games. Something wonderful about the ES and Fallout games is that not only can you set the difficulty up to what makes the game challenging enough for you, it's also rewarding, because it increases the amount of experience you gain per kill too. I usually play ES games on Expert (not Master) and it makes it challenging enough yet still dynamic enough that I can swing a battle-axe around and drop enemies left and right. Complaining about difficulty as a factor of how good a game is or isn't seems silly when there's an incredibly well made and intuitive difficulty setting right there.
As for whether Morrowind/Oblivion/Skyrim are good games or not... Well, that just comes down to preference. I grew up on PSX RPGs that took at LEAST 30 hours to beat, and I still always took 100+ hours in them because I did every possible side quest, found every legendary weapon, etc. I still was never satisfied though, because with as much freedom as a game like FFIX could give you, it was still holding your hand throughout the game. I don't like my hand being held. I don't like linearity unless the storyline is INCREDIBLE (my favorite game is a split between Chrono Cross and Final Fantasy Tactics), otherwise I feel like I'm just doing a series of chores till I reach the final boss and toss the game aside, never to play again.
There's replay value to the ES games that other games simply don't have. I can go anywhere and do anything, and I'm not bogged down by a story that I might not particularly enjoy. I like making multiple characters with completely different skill sets, morals, personalities, etc. There's so much variety that I have to chuckle when people say the games are too repetitive, or easy, or have a crappy story, because the games do what other games just don't. They immerse the player with history and lore and all those other things that make up fantasy world, and they give you choices
. Not many games do that.
But hey, it's all preference. I don't hate linear RPGs either, but I'm biased towards really good, classic RPGs. Let's just say I couldn't get far through FFXIII without getting extremely bored.