Ok, 3 attacks for trolls! 5 for giants and 27 for the hydra! Ok I jest about the hydra.
My point is we have had longstanding issues with the conversion of attacks from the WFB tabletop war game to the RPG.
In light of the new 40k RPG traits of unnatural characteristic and size. How would I rethink some basic beasties.
First - I don't want to apply this to basic races - I don't want orcs with unnatural toughness and elves with unnatural agility.
So the troll.... A good starting point. Unnatural... Strength - yes. All distriptions discuss their strength. But toughness - no - and they have regeneration to cover this. Size - hulking - +10 to be hit and -10 to conceal. Agility as move

Could be done. Lower strength a little so the brute career soul not take it to a SB of 6. Lower attacks to 1.
Ok this looks like:
WS: 37
BS: 15
S: (8 ) 43
T: (4) 48
AG: (2) 20
IN: (1) 18
WP: (2) 27
FL: (1) 10
Attacks: 1
Wounds: 30
Move: 6 (if I used size would need a speed boost trait)
Traits: fearless, frightening, natural weapons, night vision, size (hulking), SWG (two-handed), unnatural strength
Special: regeneration, stoopid, vomit
Hits like a brick, about as smart as one. Less attack spam.