Cards for reference: https://imgur.com/a/C1dnxLH

So my Spellweaver just hit level 4, and is taking Forked Beam. Guide writers often complain about this level for Spellweavers, saying how the card feels underpowered compared to Scoundrel's Throwing Knives and Tinkerer's Reviving Shock. And while it does feel kind of weird for a Level 4 card to be numerically similar to other classes' Level 1 card, I want to argue for why it's actually okay - and I would love to be proved wrong.

Forked Beam VS Throwing Knives

1. I would argue it makes sense for the Scoundrel's cards to be baseline more powerful than the Spellweaver's, because Scoundrel gets a harsher endurance limit. Yes, Scoundrel gets 9 cards while Spellweaver gets 8, but Spellweaver's Reviving Ether makes her able to last significantly longer. Scoundrel gets fewer turns, and so Scoundrel needs harder-hitting baseline cards as a result.

2. A huge part of what you're getting with Forked Beam is that 20 initiative. This is the 2nd fastest card Spellweaver ever gets until level 9, so that "20" in the middle of the card is a big part of what you're paying for. Throwing Knives' 10 is "better", but Scoundrel already gets a ton of high-initiative cards naturally as part of their kit. Forked Beam's initiative is rarer, therefore more valuable. Your other options for high initiative as Spellweaver:
   -07 Mana Bolt (great card, we love it)
   -19 Inferno (this card is level 9. You won't see it for a looong time.)
   -20 Frost Armor (Top half is Mana Bolt, bottom half is mediocre)
   -21 Freezing Nova (widely considered bad)
   -25 Crackling Air (Top half difficult to use, Bottom half mediocre)
   -26 Hardened Spikes (widely considered bad)
   -26 Flashing Burst (Considered great, but you might not have it if you picked Icy Blast - I don't)

Forked Beam is, other than Flashing Burst, the only solid high-initiative card Spellweaver gets with two workhorse halves you're always happy to play. And Forked Beam is generally stronger than Flashing Burst - a card people are very happy to pick up at Level 2!

1. The other huge part of what you're getting with Forked Beam is that Move 4 on the bottom. You're often going to be playing Forked Beam for its initiative to pair with some hard-hitting effect, and you get rewarded with a truly excellent action on the bottom that you're almost always happy to play. Throwing Knives "Loot 2", on the other hand, is something that's extremely situational, and you are almost never going to want. If you mentally place "Move 2" on Throwing Knives' bottom half, suddenly Forked Beam looks a lot better in comparison.

Forked Beam VS Reviving Shock

1. Tinkerer gets way more cards (and way more endurance), so that argument doesn't apply here. My argument would be that Reviving Shock is a much worse card, despite the identical top half:

2. Reviving Shock's initiative is just straight-up worse. It's not awful, but I will always prefer initiative 20 to 34; going at 34 leaves you open to a lot of Bad Stuff.

3. The bottom half of Reviving Shock is, again, way worse. You can argue which of "Loot 2[Loss]" or "Heal 5[Loss]" is better, but repeatable Move 4 is better than both of those, by a lot.

The last argument I would make is a much shakier one, but it's basically:

-Every Spellweaver is gonna have Mana Bolt with a Strengthen enhancement, meaning they very frequently have advantage when attacking.

-Therefore Spellweaver benefits more from multi-target effects like Forked Beam, since that means drawing more modifiers from the deck.

-Spellweaver gets two very potent modifiers very early: 2 Ice and 2 Fire, to enable Cold Fire. Neither Scoundrel nor Tinkerer get anything of the sort (that I know of) which makes Forked Beam more valuable.

So those are my arguments - please poke holes in them! The TL;DR; is the Move 4 is the star of the show, not the top half.