Cryptic Command is way too color intensive for a 3-color deck. More often than not it is better to use the mana on your turn than hold up 3 blue- this sets you back a lot more than some people realize. I think Arcane Denial is far better in that slot. Cheaper, still a hard counter, and forces them to draw. Perfect for this deck.

I got a Nekusar Wheel Deck myself, love it :)

I would cut:
- Breathstealer's Crypt: Average damage too low compared to alternatives.
- Vision Skeins: Doesn't do enough.
- Jace Beleren: It's a Temple Bell, doesn't do enough.
- Kami of the Crescent Moon: Worse than a Temple Bell.
- Jace, the Mind Sculptor: I don't feel he fits in this deck, but I would probably play him as well if I had him :)
- Magus of the Jar: If you need space, he is a bit clunky and expensive.
- Nin, the Pain Artist: You don't have room for targeted removal (that is also very mana intense, even though you are short on ramp).
- Sensei's Divining Top: You have no space for it.
- Anvil of Bogardan: Not a big fan, but could be fine.

I play:
- Bloodchief Ascension: Seems like a no-brainer. It's activated quickly in a multiplayer game and then it's an awesome discard punisher + it triggers not only off of discard.
- Ill-Gotten Gains: It's mass discard for the discard punishers and allows to pick up some of the wheeled away cards. I ended some games with Gains + a picked up wheel effect. I also play Bojuka Bog to get rid of any sort of disruption the opponents could pick up.
- Mass bounce: Especially Evacuation but also other mass bounce effects are extremely powerful with the wheel spells.
- Notion Thief: Any wheel effect and you're almost done!
- More ramp

Maybe:
- Chandra Ablaze: Another Wheel, though a bit expensive and you seem to have enough.
- Misdirection: I just love the card for commander, because it's so much fun to blow someone out with it.
- Scroll Rack: I love it with all the wheels, but it's an old expensive card. Library of Leng could be also nice, but never tried it.

There are more really good cards that i didn't mention, but I don't have those (mainly because they are rare old cards). I didn't look at the mana base.

My philosophy:
I try to build around the wheels. I add a whole bunch of wheel effects, so I'm certain I will get a few of them in each game (you got that covered). Then I add some punishers that can win me the game (also covered). I also got some ramp to set up massive wheel turns quicker (which I feel is a bit short in your list). For control we differ a lot. Sigil of Sleep interacts very well with the pain creatures like Nekusar, the Mindrazer, but I prefer cards like Evacuation. They interact well with the wheels, that are the core of the build and also work fine on their own (which makes it more consistent). Also, I play more mass removal like Devastation Tide or Damnation, since people are going to play plenty of stuff with all that card draw you provide. I make room for ramp and mass removal by cutting most of the Temple Bell/Howling Mine effects you play. They give your opponents a lot of resources but wither them down very slowly.

TL;DR: Less Temple Bell, more mass removal and more ramp to go off quicker with the wheels.

About Elder Mastery: It's hard to achieve the lock, but might be worth running. If you do though, everyone will hate you. It's like infinite turns, you won't make any friends that way. That's why I wouldn't run it.

Ok, here's the thing. Kami of the crescent moon is NOT a temple bell, he's a howling mine. He needs to stay. Crypt is better than you would expect. Howling mine jace is good, and mindsculptor is good board control. Notion thief RUINS my neku deck. I want my opponents to draw cards, not me. I do want to put a little more ramp in, but no matter what nin stays. I do like ascension, and had it here before. Might put it back. Magus of the jar is a second memory jar, but I think I will cut him for ramp. Top I will cut for library of ling.

For Spikey:
Kami of the Crescent Moon/Howling Mine are very similar to Temple Bell, everyone draws one additional card per turn. But with a Temple Bell you can decide when everyone has to draw. The problem with all of these is, that as long as your opponents don't die, you give them a tremendous card advantage. If they play a combo deck, they will get their pieces faster, a control deck will have more answers, everyone will be more likely to draw into their enchantment removal and so on. If you got Howling Mine and Underworld Dreams out and they kill your Underworld Dreams, you just let them draw cards without cost, which is huge for them. That's why most Nekusar, the Mindrazer decks are ramp into wheels to finish of the whole table at once or control into wheels to finish of the table at once.

For fun:
A fine tuned Nekusar, the Mindrazer deck can be quite quick in killing everyone at the table, i would say it's probably a tier 2 (maybe 3) multiplayer deck. But commander isn't all about winning, it's about having fun with the people you are playing with. In that sense the group hugging aspect of Howling Mine is great. Everyone get's to see more of their deck and play more stuff and with some politics you might still be the last man standing. Spikey's Nekusar, the Mindrazer deck on the other hand is way less fun to play against. Btw Flux goes in the same direction, your opponents can sculpt a nice hand for a few points of damage.

Notion Thief doesn't ruin your deck. In a 4 player game you draw 28 cards and they discard their hands with a single wheel. You will have a full grip of everything you need to win the game and they got nothing. I am a blue mage through and through and this turns me on so much. It's also just a two piece combo and one half is like a fifth of the deck. Also, they have to kill Notion Thief to refill their hands, so he won't stay for long.

The nice part about Breathstealer's Crypt is the knowledge of their hands you gain. But that cuts both ways, they see your hand as well. The damage it does is very dependant on the decks you play against, which I don't like that much. And you cannot kill anyone with it. It's a bit better in the group hugging deck, since you are incrementally killing them and it becomes quite good against bad players.

Jace, the Mind Sculptor isn't good board control in commander. It only bounces one target and it has to be a creature.