(Because this is heavy to read, I have my points summarized at the end)
1. Improved Clan Wars / New Clan Event Mode
Personally, I don’t actually feel like I am battling against “Clans.” I want to see more interaction between clans during the river race, such as new items that could affect the result of the race. I’m thinking of something like magic items that could increase the points your clan gets for the next 5 battles (anyone can use the boost), magic items that decrease the points of one random clan, items that target the leading clan’s points, stealing other clans’ points, reflecting the effects of a harmful item one time, and so on. They could be earned during the first 3 days of the river race, where you’d get clan war coins instead of points, and buy items in a special shop. Items can be activated by the person who bought that item (except for the reflecting item, which will be triggered automatically). This will also make clanmates communicate during clan wars to form unique plans for their clan.
I have another idea for clan events: a PVE boss battle like the one in Clash Mini and Clash Quest. Instead of fighting a tower, make a single boss that will stand where the opponent’s king tower would normally be, and clanmates have to defeat the same boss together. The boss will summon troops and use special moves, like long-range attacks, AOE melee/long-range attacks. To make things harder, at the start of the boss battle week, 20 random cards will be distributed to each clanmate, and they can only use the cards given during that week. As compensation, clanmates are allowed to enter the boss fight together, up to three people, to make the best possible combos to defeat the boss and earn sweet rewards.
2. Improved Season Shop / Event Modes
At the moment, the Season Shop and event challenges are just not fun to play. Instead of giving useless banners, I think it would be better to remove Evo Shards from the shop and make them the final rewards for the challenges. For example, 6 Evo Shards per season (4 of the featured one, just like Battle Ram now, and 2 wild shards), and since most seasons are four weeks long, maybe put 1 featured shard in each challenge and 2 wild shards in alternating week challenges. This way, more people would actually try event challenges, which would mean they are more likely to spend gems or buy season passes as well. And PLEASE ADD MORE versatile rewards like boost potions, trade tokens, and LUCKY DROPS TOO PLEASE.
3. Improved Daily Quest and Path of Legends Rewards
I would like new, varied daily quests instead of the same ones we get every day. Also, crowns as rewards are just useless, as a normal player who plays around 3 games per day will finish their Royale Pass about halfway through the season. So I need new quests such as “win x games with Knight,” “win with all of your towers remaining,” “play x elixir cost cards x times,” and “spend x much elixir.” Because the new quests I’m suggesting are more time-consuming and harder, I’d like to see improved rewards as well.
I consider myself to be one of the biggest fans of Clash Royale and have played the game since its release (although I have lost my account and my current one is just five years old). Although I still think it’s one of the best games to be released on Earth, I would like to see the Clash Royale era return, when it was dominating the game market.
Please consider my suggestions. And I would like to see new star levels as well. 
Summary:
- New clan war and boss for clan events.
- More wild shards per season.
- More daily quests.