A few suggestions from long-time player (balance TH 8, clan-ban, etc)
Hey guys, let me preface this by apologizing for the long post and give some quick background info. I've been playing for about a year and have a mid TH9 account and mid TH8 account. I don't gem, aside from buying the extra builder (I'm a grad student so that's where all the money goes :() and I am part of a very active 100% war adult clan. You'll never see me on the top leaderboards or posting sponsored videos, but I love the strategy and have a pretty good feel for the game. That said, I have a few suggestions that I think would improve the game we all secretly play while we go to the bathroom at work.
Make Wizards Pull the Trigger: Once a wizard starts his attack sequence, make him follow through no matter what. Wizards will make you pull your hair out if you ever try to take out some clan castle troops with them. You watch them find a target, roll their sleeves back, rub their hands together, wind up and then - nothing. Once that one archer they were looking at gets killed they completely stop and start over. Often, a bunch of troops are in one pack and vulnerable to splash damage yet the wizard gets cold feet and starts all over while arrows rain down on them. The long reload time makes them hadouken a whole bunch of nothing. Make it so that when they start their attack sequence they complete the attack before switching targets, even if the target is destroyed.
Buff Hogs against Skeleton Traps: Adjust skeletons to only do 1/2 damage to hog riders.
The purpose of this is not as much for hog lover as it is for all the warring TH 8's out there. When the Halloween update came out it effectively killed the hog rider as a viable war troop. I'll admit, I love hogs and I think they were fairly balanced. As a TH 8 you had to make a considerable investment of 50,000 DE to get the hogs to level 3 before they were viable, but once you did they provided a completely unique attacking strategy. If you hit a base with too many open spaces or were just a little too late with that last heal spell *poof*-everything disappears. But when you got it right they were effective. The additional mortar definitely nerfed them by bringing in more splash damage and giving hogs 1 more building to take out before attacking the king that has been wailing on them for the past 90 seconds, but skeleton traps killed the hog rider. With two level 2 traps, those skeletons do 150 DPS and just chew up the hogs who are too far into the base for archers, wizards or dragons to help clear the skeletons off their back.
As a result, TH 8's are essentially 1 dimensional in war. Against any decent base dragons are by far and away the best attack strategy now, and it boring. GoWiPe is usable but unless you're packing witches in your CC you're shooting for a 2 star at best. At TH9 there are so many viable options (GoWiPe, GoWiWi, DragLoonian, Quad Lavaloonian, etc.) which makes it a lot of fun, but not at TH8. Help give the TH 8's some other attack options for players to add variability and balance to the game.
Gem War Bonus: Add gems to the war bonus loot.
Pretty simple idea that rewards warring (which drives the game's popularity and is obviously a focus of supercell after they nearly doubled the clan war bonus a few months ago). It doesn't have to be a lot and should be added ratably like the current gold/elixer/dark elixer bonuses. 1 Gem for every 25-50,000 gold/elixer would be a fair amount.
Count War-Base Troop Donations: The troops donated to war bases should be included in a player's donation count. This one really feels like a no-brainer to me and I don't know why it hasn't been implemented already. Donating troops for war base defense should could towards a player's troop donation total and towards the "Friend in Need" achievement.
The Clan-Ban: Allow leaders to permanently ban players from requesting to join the clan. There could be a list available to only leaders/co-leaders showing the banned players and allowing them to un-ban them as well.
This one is pretty simple and hopefully you never have to deal with it but I know a few of you out there have experienced this. We kicked a kid about 6 months back who just wasn't pulling his weight and, as an adult clan, wasn't the best place for a 6th grader. However, every week or so he sends a join request and his message varies anywhere from annoying to nasty. Sure, its easy to reject but its a pretty annoying nuisance we endure that can easily be fixed. Again, I'm sure 95% of you don't have to deal with this but the 5% who do know how annoying that is.
Clan War Chat: Create a chat or message ability so that warring clans can message each other. Sure, your first concern is vulgar/hateful trash talk and that is a legitimate concern but its also a concern on global chat as well. Make it an option for the leaders to either enable/disable the chat so they clans can talk to each other only if both leaders enable it. If, at any time things get out of hand or either side gets tired, they just disable the chat and its over. Plus, there would also be the "report" button we have in global chat to help moderate things.
Adjust the Valkyrie
This one is last because I don't have a great solution here. It's no secret that the valk is the least used troop and for good reason. She spends too much time running around and not enough time doing anything of value. The last AI logic adjustment attempted to maximize her damage by hitting as many buildings as possible but unfortunately it makes her worse. Once once building is destroyed she'll stop, run to another spot and try again even if the other bordering structures are still standing. All the while she's eating cannonballs and x-bow blasts. One idea is to let her continue to attack until every building she attacks is destroyed. Or give her an ability (for example, she can be damaged by traps but will never set them off) to add value to her.