Seriously, every 6 seconds you get to a trade that lets you win because of your W. You can poke with Q. You can peel with E. You can LITERALLY SAVE YOUR ADC with your ult. You have superior vision via ghosts. Comon.... =D How does that not sound stronk?
IcyPepper2 votesDue to her passive, I believe she's likely to take more cs and kills than necessary.
Problem however is that due to her only real utility is in her ult, reliance on items and damage dealing kit, she's not a reliable support. It would just be a double-adc lane.
Knight SoIaire 1 votesyou forgot the vision from the ghost
but yes ... the discussion is about her being just a random minion that saves the adc and the question is if that is enough to make her viable
while other supports do more, noone of them can save the adc so easily and reliably
IcyPepper2 votesIf someone did want to go Kalista "support," double utility adc bot lane could work.
Unfortunately, I was going to suggest Ashe but she's getting a rework. I'll have to see how well she does with her passive slow now that you can't power level it for a permanent 
.
However, the difference between Ashe and Kalista is their level of utility. Yes, Kalista has a "save the partner" option, but it only works on one person. Lulu's ultimate is targeted and can affect anyone including herself, Soraka's heals everyone on your team, Janna pushes every enemy away, and so on. I don't think Kalista works in that regard, even with ghosts (other supports are going to buy wards, and junglers like me know how to destroy ghosts without being detected), because she can only support her partner, not her entire team. A support needs to be able to support everyone, not just one person.
EvilRabbitt1 votesJust tried with Jinx, and I think you are right. Double utility/poke for lane. All in with Jinx was a disaster- we had our burst, but the mf murdered us.
Knight SoIaire 1 votesbut lulus ultimate and even kayles ultimate can fail , basicaly all supports can fail or be outplayed or outmatched
for kalista its just pressing a button and her adc is 100% safe (stasis should negate even ignite and other sources of true damage )
kalista is 100% sure to save her adc with that ult, but is that enough to make a support ?
50000000000000001 votesMartial Poise? How would that make her take more CS/Kills?
IcyPepper1 votesno, the other passive. The soulbond one.
50000000000000001 votesThe sentinel passive? The damage bonus goes to whoever hits last, I think.
Silent Pace1 votes[deleted]
IcyPepper1 votesHuh... I'd have to check that one out.
Drunk Rummate1 votesMaybe. Coin + sightstone and she's pretty useful. Lots of vision control, decent damage in an all in, pretty good poke in lane, life saving ultimate.
Not really sure how she could be better than a Braum or Thresh though.
Arcade Andrew1 votesI tried convinving them of this a long time ago, then I got reported for trolling when I tried it and everyone told me I deserved my punishments
KidSpectre1 votesIt's kinda like support Ashe, imo. You get the utility, sure, but without items you're just a sack of potatoes.
EvilRabbitt1 votesAshe support works pretty well from what I've done. I usually take 1/3 to 1/2 of the enemy adc or support during each trade while we lane. =) Kalista though =/ Utility/poke or nothing. She doesn't need items to get 12/14/16/18/20% enemy max hp in magic damage every 6 seconds. It just takes coordination. Ashe doesn't need items early either, just get W first then wait for lane- pop focus based crit and W each time you get the passive stacked. Just my experience.