I would like to see some weather changes too. Don't get me wrong, current state of weather is "okeish" when you compare it to closed beta. I just would like to see it as less oppressive mechanic and more as a foundation for combo/synergy with other cards. Here is my idea:
First, weather should spawn on both sides of the board (you still pick the row) and we should have some weather immune units back in the game. In my opinion it encourages smart weather usage and deckbuilding, and just bring more variety into the game.
Now the biggest change, weather no longer deals damage every turn (at least in bronze/silver slot). Instead it deals initinal damage after it's played (something small, for starters let's say 1 point of damage that ignores armour). This damage would be also dealt to every unit that enters the row with weather (either moved or just played into it). Weather in that form could still work in Skellige wounding decks for instance.
To make weather more worthwile, I would expand on synergy mechanic with other cards. Let's take a foglet deck for example. You play fog, bring foglets from your deck on the board, your ancient foglets are boosted when they are in the fog (currently when fog is on board). And that's it. What if we could have more cards that work with weather, for example, Fiend could lock target unit and reduce it to 1 Strength when you target unit in fog (or he works as he is now when you play it on unit not in fog). So basically you get extra "umph" when used with fog, but it is still viable card without fog on board.
Bear in mind that this could also work outside monster faction. For instance, Alzur's Thunder could have additional effect when played on unit in rain, let's say it forks to adjacent unit and deal half its original damage to it. So 7 to main target and 3 to one adjacent unit.
Last thing that is completely optional, but may expand design space for Gwent: weather applies special status effects to units. For fog we could call it "obscured vision" or "blinded", for frost it could be "cold" and for rain "wet", you name it. So from earlier examples, Fiend would affect unit with "obscured vision" and Alzur's Thunder "wet" units. That way we could have some cards that apply those status effects outside weather cards, for example some mages could fit into that role, or cards like Wild Hunt Hound that could just apply "cold" to units on enemy row when played instead of just spawning frost.
Summary of changes and some ideas for weather cards:
Biting Frost - Apply frost to a row on both sides of the board. Damage all units on those rows by 1 and apply "cold" to them.
Impenetrable Fog - same as frost but apply fog and "obscured vision" status.
Torrential Rain - same as frost but apply rain and "wet".
Skellige Storm - Apply fog and rain to the same row (we have unique art for it in game anyway). Deal 2 damage and apply "obscured vision" and "wet" to units.
or apply fog or rain on 2 rows (you can go with 1 fog and 1 rain row, or 2 rows with fog/rain). Damage all units by 1 and apply coresponding "status".
White Frost - same as skellige storm but with frost and fog on one row.
or 2 rows with frost/fog
Merigold's Hailstorm - as skellige storm but with rain and frost
or 2 rows with frost/rain.
Ragh Nar Rook - 1-2 damage to all units in a single row after you play it, then 1 damage every round. Played on both sides of the board? Maybe it could stay in it's current form and just be played on both sides of the board for ultimate mayhem. Don't know, i think it is ok for gold weather card to have damage over time effect on it, but numbers just need some tweaking.
Drought could be changed to bronze card and apply "dry" so it could work with fire based cards.