Dust him and every day you will regret the decision. As an elemental shaman player (if I have to be more accurate - jade elemental) Kalimos is an AMAZING card. He is great, because he has a strong impact on the board, he's very flexible, because he can be used in different situations. Heal, AoE, sometimes burst (finisher), rarely board presence. This card gave me a lot of wins, when I mainly faced aggro decks, mid-range ones and sometimes burn back in Un'goro. Like asmodeus said, the bad thing about this legendary, is that blizz won't introduce a good designed one in the near future.
However the issue why he doesn't see any play, is because in this meta jade dudu and raza priests are the dominant decks. The AoE can't clear beefy jades, the heal can be matched with 6 pings. Tbh the (jade) elemental decks always felt fine (fair and also strong). They can deal with faster ones, but not that much against slower. Spirit Echo helped a lot, but as some users commented in this forum, making that board state, where we can get a lot of value from it, is kinda hard. It gets worse with the fact, that shamans lack card draw, so finding the elementals, activating the chain and on top of all making the aforementioned board isn't easy. However elementals were always an essential part of the shaman class, it's just a matter of time, before blizz introduces card draw and reactive 4 or 5 mana minions. I'm absolutely very optimistic about its future , because there was also a comment about the Hex' nerf, how the devs will give us some support, which should go in line with the new change.
Heyyy another Jade Elemental player? High five! =P
I suppose the draw can be a little rough. Of course my deck has only one Mana Tide Totem and one Servant of Kalimos due to my collection. xP Do you find that two of each isn't enough though? Have you considered running Fire Fly or maybe Igneous Elemental (my preferred) to feed elemental chains? I find that minions that make more like these and honestly some of the Jade cards can substitute for card draw in at least some cases. But your deck I suspect is better than mine since I don't even have Kalimos (I have Hallazeal the Ascended instead) so I'm wondering what your input is.
Not... technically off-topic since the subject is whether or not Kalimos is good and this is a deck for him? xD
Best dust advice: do you need dust *right now* for a specific card/deck?
No - then don't dust it
Yes - as the card doesn't see competitive play.
With that said - the card is pretty good, and fun, and great in an elemental deck. Elementals was a thing, when Un'Goro launched, and has disappeared. Just remember, Jade Druid was also a thing when MSoG was launched, and then mostly disappeared for a while, until KTF.
If you would like to hear more tips, I suggest taking a look at the deck in my signature, as I have written a highly detailed explanation for some strategies and cards. I'm still going to answer your questions in this post (in the next paragraph however). Before I do that, I highly recommend you and the users in this forum to try out the wild versions of this deck, as in my opinion those decks function the way the hybrid deck is meant to be played. Normally I give market_show's deck (here) as an example. Why? What I really like about his deck, is that it's relatively cheap - you don't need the fancy wild cards to make the deck strong. My advice would be to include the following cards, as they give it a little push: Ancestral Knowledge instead of the totems, Brann Bronzebeard, Skulking Geist (good against jades and hinders the win-condition of other ones, renolock) etc.
About your questions: First off - there is something, which I learned from playing jade elemental all those 4 months of Un'goro. And that is, the card draw is absolutely essential in this type of deck. This is what makes the difference between "I won a game" and "I lost a game"*. I may never reach my answers, the elementals or the win-condition (jades). So try to maximize the draw options in your deck and at the same time try not to make it too much diluted. In the deck description I said, that Hallazeal can safely replace 1 copy of Servant, as you can plan your future turns better this way. Fire Fly is very strong in this deck, especially when combined with Flametongue Totems. The problem is, when you top-deck one in the late game, when you want to draw something else, something bigger. However Igneous Elemental isn't very useful, as I see it as a slow card, which doesn't provide enough synergy. Maybe in the future it will find more use in elemental decks, but just not now. The tokens will never replace the card draw mechanic, as like explained, a 1/2 token can't be compared to the removal Hex. About Kalimos - he is definitely a strong card, but you could hold on to the dust for now. Since there aren't many options with him (only few different decks), I can advise you to wait, until we see more support.
*Note - of course, playing correctly, aka managing the resources in a hybrid deck like this, plays the biggest role for the outcome of the match.
Its worth keeping just for that sick intro music
It`s a strong Card and it will be in Standard for ~2 years so keep it! Just wait for stronger Shaman or Elemental Cards
Best dust advice: do you need dust *right now* for a specific card/deck?
No - then don't dust it
Yes - as the card doesn't see competitive play.
With that said - the card is pretty good, and fun, and great in an elemental deck. Elementals was a thing, when Un'Goro launched, and has disappeared. Just remember, Jade Druid was also a thing when MSoG was launched, and then mostly disappeared for a while, until KTF.
Tested the tempo elemental deck idea and seems to be working okay. Similar to the rogue version, but with Shaman's special benefits.
First off - there is something, which I learned from playing jade elemental all those 4 months of Un'goro. And that is, the card draw is absolutely essential in this type of deck. This is what makes the difference between "I won a game" and "I lost a game"*. I may never reach my answers, the elementals or the win-condition (jades). So try to maximize the draw options in your deck and at the same time try not to make it too much diluted. In the deck description I said, that Hallazeal can safely replace 1 copy of Servant, as you can plan your future turns better this way. Fire Fly is very strong in this deck, especially when combined with Flametongue Totems. The problem is, when you top-deck one in the late game, when you want to draw something else, something bigger. However Igneous Elemental isn't very useful, as I see it as a slow card, which doesn't provide enough synergy. Maybe in the future it will find more use in elemental decks, but just not now. The tokens will never replace the card draw mechanic, as like explained, a 1/2 token can't be compared to the removal Hex. About Kalimos - he is definitely a strong card, but you could hold on to the dust for now. Since there aren't many options with him (only few different decks), I can advise you to wait, until we see more support.