Thanks to that 1.07 nerf, Firestream is about as useful as teats on a male. And doubly so when you reach Blood and Wine and NG+. I have five different mods installed for the sole purpose of just making signs useful in late-game. God this oversight is destroying my desire to replay the game. CDPR, please don't ever nerf abilities in your single-player games ever again. Better an ability be overpowered than worthless. Thanks, appreciate it.
The game was designed to work (and works perfectly fine) for a
standard game between
Levels 1-60(ish). That's far higher than pretty much anyone will get playing through the main quest + HoS + B&W. The game was NOT designed to work with NG+, scaled enemies, or Levels approaching 100. These were features that were worked in after the fact because of player demand, but there's no way that the foundational design of the game can be overwritten to ensure everything works without issue. It's not how the game was built.
Therefore, once players and enemies start getting into NG+ (especially with scaling), the way the game handles resistance scaling may make certain enemies immune to certain signs / effects / attacks. Technically, you're "off the charts". (The charts are there for a reason. NG+, enemy scaling, etc. largely ignores the charts and just does the math.)
In short, the game was designed to be played through once, ending around level 60 at the most, with no grinding. It is
not a Dark Souls / Diablo / MMO experience focused on endless scaling, challenge, and loot. Also, Witcher signs are not really meant to be the same things as "spells" in other games. Their only supposed to be things that give Geralt a bit of an edge. (The way Aard and Igni work is especially overpowered, imo. But fun!
)