End game is fine, Coil is the very best gear in the game and also the hardest to get. The only catch with Coil gear is that it has a few deficiencies since it's optimized in a certain way, but its still the best gear in the game for most classes. Relic weapons are hardly an achievement, a good number of people in my FC are on their 4th or 5th, and they are so easy to get because they are pretty much absolutely required for Coil. Not sure why you are grinding CM or AK to begin with, both are extremely slow. Only reason to do AK is Mythology, and even then Coil is the best source, and a good coil group should be on turn 5, which is a 150 of your mythology cap. Then you only need 3 AK's a week for another 120, then 3-4 Garudas or something.
So I don't get it when you say "endlessly repeating non-challenging content". The easiest thing we do repeatedly is Titan, but that's because we 5-6 man him and sell the rest of the slots for gil. Praetorium may be easy, but in a FC run we do silly things like try and get each other killed or leaving all the bits up on the final boss.
Also, I'd like to add that you don't NEED to grind anything really. The crafted sets such as Vanya are actually better than Darklight, especially when HQ'd. Only catch is that they are expensive.
Coil is incredibly well tuned. Turn 1 is basically a "should you be in Coil?" gear check, Turn 2 requires planning, Turn 3 can be done in 5 minutes, Turn 4 is a really well balanced gear and planning check, and then Turn 5 is just everything on steroids.
I come from EQ2 raiding, everything in FFXIV looks easy to me...
My group did Garuda on the 1st try, Titan the first night (phase 5 on the 2nd pull) - the most overhyped encounter I've ever seen.
Coil 1 the first night, etc.
EQ2 end-game encounters (especially contested mobs) make FFXIV mobs look like CSI compared to The Wire.
But I could live with Coil...
If I didn't STILL need to run AK for Myth stones 4-5 times per week.
I just can't be arsed. I fall asleep during AK.
I'm not even joking. I can't force myself to do one single run more.
The idea of ONE end-game instance where you actually hope for loot is beyond ridiculous in my book.
And it's become way to boring to run just Coil and wait for the November patch.
You can run CM for currency and get the full DL set.
You get the best weapon in the game by beating 2 relatively simple mobs and one a bit harder.
Then you run one instance per week worth doing and twiddle your thumbs the rest of the time or re-run AK and stuff for stones...
You can get end-game gear very close to the best (DL, AF2 sets) by re-running simple instances that present no challenge.
In fact, you do that, odds are with time invested you'll have better gear than me running Coil but NOT piling up Myth stones in AK.
This game has potential...
But being forced into grinding without even hoping for drops is not my idea of fun.