Expanding the gaming audience has come at the cost of making games simpler and easier, Epic Games design director Cliff Bleszinski has said...

..."It feels like in this current console generation that we've taken a lot of steps to grow the audience and what I think's happened is that the games have become more linear and easier, so it feels like a lot of quick-time-events," Bleszinski told Xbox360Achievements.

hoping to present a challenge for players.

if you just want to see graphics

every other mode will be hard in this game and you will die

I always find it interesting when there's an interview with developers like John Carmack, Gabe Newell, or Shigeru Miyamoto. But I have never, ever found anything interesting from the gob of Cliff Bleszinski. If he actually means everything that he says, he is either blatantly lying or completely clueless as to what goes on in this own company and in the game developing industry. He's almost as bad as Bobby Kotick.

so their hard is not hard enough, but when it actually is hard enough it's too hard?

Unless you mean that they way they go about making it hard, is uninspired. well, yeah I guess.

Yes you're right in that I guess. FPS games generally aren't about timing movements correctly. Then again, there are FPS games where learning attack patterns of enemies is important. Why not make an FPS game where you can be hit only 3 times and evading attacks of enemies is more important than soaking up bullets until you reach the safety of the next indestructible crate.
You'll probably get a game that plays quite a bit different than Call of Duty or Halo, but it would most likely work. Parts of Metroid Prime are an example of this and pouring a game like Vanquish or P.N.03 in a FPS mould might be a possibility.

so their hard is not hard enough, but when it actually is hard enough it's too hard?

This is an interesting topic. It depends on what you define "hard" as. Games can be hard for a variety of reasons. In my view, some games are challenging because they require a high technical or even motor skill set. Some games are hard because they require very fast decision-making, even if the physically-coordinated requirements aren't very rigorous. Some games are hard because your avatar doesn't have the stats or gear to adequately face a challenge (yet). Some games are hard because they throw ridiculous challenges at you that aren't really meant to be overcome (here's looking at you, Diablo 3 Inferno monsters with a nearly-impossible affix combination). Still yet, some games are hard for even worse reasons than the previously listed one: poor gameplay mechanics. Often, challenges in games come in combinations from this shortlist. What one person might call "hard," I would call cheap bullshit. On the other hand, somebody might look at a game like Contra: Shattered Soldier and call it incredibly easy, which it is, after you're "rehearsed" it enough to get it right. At that point, it's all muscle memory and not necessarily raw skill. A dissertation could be written about this, but I guess I'm just posting to point out that in this discussion, the concept of difficulty is a slippery one to define.