Actually, the beta wasn't stale even during the last 6 months with no updates. Greatswords still had the highest winrate, but many new competitive decks emerged during that period.
For instance, Foltest with redanian elites and witchhunters, tempo reveal Kalveit with Letho and Regis, dwarves anti-GS control deck (with Ida, Triss, Ithlinne and thunders). Sure, some were reivented versions of old decks, but it's kinda hard to come up with entirely new decks with a limited amount of cards, innit?
But overall there were over 20 (twenty!) rank 20/21 viable decks equally distributed across all 5 factions. I already made a post with a list. It's a shame we no longer have a public data from gwentup with winrates.
How many top tier decks are there in HC? Around 8-10?