it says it was removed because it was rarely bought , but some people had to change their strategy , for example my strategy was to quit heimer , because i was playing with him because of the spell vamp and it was fun..
Electro5221 votesRiot wanted to change how Spell Vamp worked in general. So, WotA was removed to make way for new items.
Gunblade still heals, but for Heimer turrets, I don't think it's that great, since I think they're considered an AoE ability. If you want decent healing, I'd suggest 
RoA. It heals based off of mana spent, and returns mana as you take damage.
SirΤeemο1 votesi agree with you , but they didn't made new items , gunblade death dance etc. existed back then as well. they removed WOTA , because at some point (in my opinion) they lost it and made it , they reworked it 9 times . they removed/added/buffed/nerfed too many stats only over on season 1 and season 4 . then they might forgot about it , and removed it later on on S6 v9.
Sohleks1 votesBecause they thought it was a trap or Vlad problem. They decided Vlad resident sleepering up mid lane with a full tank item Spirit Visage was healthier instead.
SirΤeemο1 votesbut after all , removing 1 item because of 1 champion doesn't seem like a solution, they could nerf vlad's healing
zlumpy1 votesHonestly...I bet it was because they couldn't balance it around mages like vlad and swain that had heals already built into their kits.
ProfDrDeath1 votesBecause Spellvamp, as a stat available on items, would not be balanceable to be non-trivial while still fulfilling its purpose. Note that Spellvamp here purely refers to "healing based on spell damage" instead of "healing based on all (physical) damage".
Sohleks1 votesWe still have it though, but on a burst item. 
Why is it okay to exist on a burst item? Although its remaining time allowed to be viable on mages is probably closing.
Dominick Destine1 votesWe still have it though, but on a burst item.
Why is it okay to exist on a burst item?
Gunblade isn't particularly bursty.... it's more utility than burst.
ProfDrDeath1 votesGunblade's problem, as you identified, is its combination of an instant-burst, point&click item with the sustain effect - although it is mainly problematic on two champions right now: 
and 
. Both of them are having access to high-throughput single target spells to abuse without particularily needing too much mana sustain.
But, another point: What Gunblade has is not Spellvamp, as in "healing based on damage dealt with spells". Gunblade has Omnivamp, meaning "healing based on damage period".
A Basic Island1 votesbecause spell vamp as a stat was/is inheritly broken and it doesn't allow for much design space. Champions like vladimir had very little to do with the removal of spellvamp in reality. Most people like to blame him, but he has next to nothing to do with it.
All you gotta do is look at how LB functions with GB currently and how much she heals off of it. That shouldn't be allowed, and it will likely get nerfed very soon.
Dominick Destine1 votes[{quoted}](name=A Basic Island,realm=NA,application-id=3ErqAdtq,discussion-id=52MId7Q6,comment-id=0004,timestamp=2017-04-30T10:27:56.374+0000)
Champions like vladimir had very little to do with the removal of spellvamp in reality. Most people like to blame him, but he has next to nothing to do with it.
The developers openly stated that Vlad was one of the major reasons the item was removed. It wasn't a secret.
Once spell vamp was removed, they could begin reworking him.
Best princess EU1 votesafter they destroyed spellvamp it was only built on vlad and not a single other champion
so xypherous's logic was "we don' t need this if only one champion buys it and makes him imbalanced" so he removed spellvamp and balanced vlad around not having spellvamp
Mordepool1 votes[{quoted}](name=Sanji fanboy,realm=EUW,application-id=3ErqAdtq,discussion-id=52MId7Q6,comment-id=0005,timestamp=2017-04-30T10:32:57.979+0000)
after they destroyed spellvamp it was only built on vlad and not a single other champion
so xypherous's logic was "we don' t need this if only one champion buys it and makes him imbalanced" so he removed spellvamp and balanced vlad around not having spellvamp
I built it on Morde all the time. Was a rare non- mana focused item that gave Cooldown reduction.
Dominick Destine1 votesI built it on Morde all the time.
Yeah it was pretty solid on Mord.
I'd also argue that it was decent on Swain and Kennen, but still Vlad was #1 user by a huge margin.
Dominick Destine1 votesIt only functioned on a couple of champs .... and when it did, it worked INSANELY well.
But for everyone else it was pretty much useless, making it a balancing nightmare. It was the removal of this item that allowed them to finally rework Vlad.