This is my opinion, but I think one of the weaknesses of many factions is a lack of a sufficient consistency, tall punish and tech cards (locks, purifies etc).
The reason why this is a problem is because whenever a faction lacks these things, they default to the usual neutral cards such as Oneiromancy, Heatwave, Royal Decree. Which reduces deck diversity and makes every deck feel similar.
This also causes a lack of leader diversity. Take NR for instance– the reason why Inspired Zeal keeps being used in due in part to the fact that NR's tall punishes are Seltkirk and Anseis. (I know Bloody Baron works as a tall punish, but its also not enough).
SK is actually a great example of tall punish diversity that is done well. You have a lot of ways to destroy cards which synergize with different leader abilities. Junod works with Reckless Flurry, Blaze of Glory + Jutta, Hjalmar works in a warrior deck, Morkvarg & Tyyrgvi in Pirates, Champion's Charge or Madman Lugos works with Patricidal Fury. The result is that you have greater options when it comes to deck building.
Where SK lacks is in consistency cards, which are limited to Blood eagle, Raiding fleet & the crows that summon themselves.
So yeah– it is my belief that we have more consistency/ tall punish cards, we will have less deck diversity due to defaulting to the "optimal choice.
Source: https://www.reddit.com/r/gwent/comments/qmboy5/every_faction_needs_good_consistency_good_tall/