Most of the time only ST can make Merigold a 30+ points silver cards, or maybe SK with harpoon but that deck doesnt synergy as well as ST with hailstorm. Rest of the time merigold becoming big is because opponents have riddiculous high tempo cards.
Henselt into siege support creates 19 points with potential of buffing 3 points to every unit spawned after that, or discard SK with 30 power bronze units, 26 power shani play etc..
If you played control vs control matchup, like vs weather deck, merigold can only deal like 10-15 points, which is OK for a silver.
And in the case of 30+ merigold in ST, one thing should be consider is other cards combing with merigold have less value, for ex zoltan becoming 11 point gold cards, doregaray drowner becomes 10 points silver cards, or dwagitator 9 points bronze etc,... In order to make merigold big, you must save lots of cards in your hand and most of the time in trouble catching up with opp. That makes round 1 and 2 vulnerable, you either has to sacrifice your merigold tools to get tempo, or has to use merigold earlier to save you from 0-2 and make lots of remaining cards next to useless.
If you let merigold user has a long rounds 3 ( dry pass round 2 for ex ) or play extremely high tempo cards with low agility or nothing to protect your units ( heal, shield etc, ... ) it is not merigold alone that makes it a godlike power swing.
The only case where if having merigold becomes unfair is when tempo vs tempo, but the chance of getting it just from drawing is same as getting a gold or another silver card, which could also make a big play.
