A lot of thought goes into Kara, especially if you’re not getting the right draws.
I’ve seen several of Duelysts S rank+ players making these posts about how they ran straight to S on a smerf with default cards and Kara, posting the decks and explaining it even, but when I took a crack at it I went 2/2 in the first 4 games.
Now sure, I certainly am by no means a great, or even good player some days, but if they can soar to S rank, and I can’t even move reliably through Silver without knowing the game?
Despite this, Kara can be broken, or useless.
Look at it like this:
For the cost of one you can potentially give a total of 6/6 to your hand.
That certainly sounds broken.
With that said, you have to pay cost for these minions so it’s not like you’re swarming with steroid enduced rage.
Plus, in that scenario, you have 0 spells.
Rush aside, these minions can be despelled before damage is done.
But then you get, "But I don’t want to HAVE to run despell."
You need despell in this game. Seriously xD
Removal at the very least.
So now let’s look at Saberspine directly.
As the game progresses you will cast spells, summon not super boosted minions and the like.
Damage will exchange between players, but your hand will gradually shrink, unless you run draw, which gives you less BBS targets.
So, if the enemy manages to despell your mildly boosted minions and control well enough, you drop Saberspine at say, 6/5 for 3 mana.
That’s 3 boosts, six turns of keeping just him in your hand instead of trying to manage what’s on board.
At this stage it’s late game unless Kara open handed the Saberspine.
Your opponent will generally by now have dropped a larg enough minion to distract Saberspine from going for face, so it can also be looked at as a 3 mana removal spell, which is far from unheard of, if it doesn’t feel the need to go for face.
If the rest of your hand didn’t look great you can get overwhelmed.
Do I think it’s fair when it happens to me?
Of course not, but in a certain light that’s what Kara is for.
But from a sheer numbers game Saberspine is not the problem.
The game as a whole is the issue.
It’s a 1 drop spell that on average provides three 1/1 boosts to unknown cards; potentially more making it broken, potentially less making it highly negligible.
Ultimately it could for a total of 3 uses provide say, two 3/3 boosts, two 1/1 boosts and some scattered mess, for only 3 total mana spent. So, that’s an uncertain total of, call it 10/10 for 3 mana. Iffy on the balanacing and numbers there, but you get my point.
If her BBS was to be reworked to say, give 2 random minions in hand 1/1, or to do the same thing but wear off after 2 turns, I feel it would be a great deal more balanced.
TLDR
The Spell is very good, situationally broken, but as a whole not inherently.
Suggested reworks right above this.
Amateur math and a handful of scenarios presented.
Stuff.