The Hearthstone team has not given up on making the Warlock's Lakkari Sacrifice Quest a viable archetype, according to a post on the official forums by game designer Dean Ayala.
"We like the Warlock quest, agree that it's currently not very powerful," his post reads in a response to a poster asking how the quest could be buffed.
"It's likely there will be more support for it in the future. Can't go into specifics but it's one of many archetypes we'd like to have a bit of extra support for."
The Lakkari Sacrifice card was introduced with this year's Journey to Un'Goro expansion. Once the quest has been played and you've thrown away six cards using the Discard mechanic, a 5 Mana Nether Portal card is added to your hand. Once played, this permanent portal summons a pair of 3 / 2 imps onto the board every turn.
It's a deck type that was experimented with heavily in the early days of this year's first expansion, but it failed to prove competitive in the long run. For those unfamiliar with the mechanic, the Discard system allows you to play unusually powerful cards, albeit at the expense of one or more randomly selected cards in your hand being destroyed.
As a result it's a divisive playstyle which many Warlock players find frustrating. Fortunately, a follow-up post from Ayala clarified that players need not fear an imminent influx of cards that will force the mechanic into the competitive meta.
"We don't have any plans to make discard the core theme of any set in the near future. We do think there is room for a one-off card to help out."
So, expect an extra card or two in the next expansion to increase the viability of Lakkari Sacrifice, but without making it a fundamental part of the Warlock experience for the next year or more.