I know there is a strategy thread out there, but I don't want to go there. Some feedback for the @Community-Managers . And I'll try to be less salty than usual 
I think the reward system and matchmaking must be tweaked. Also the whole "monsters used on defense can't be used for attack" does not work for me.
(1) Rewards. The number of points a team can score is directly tied to the amount of eligible monsters they have. Some restrictions are pretty challenging, even we (a team with over 2 million MP) could place only 15-20 monsters on the back areas, and won't come close to sweeping the enemy fields.
So IMO it would be sufficient to have rewards based on (a) points achieved and (b) win or loss. No tiers. Teams with low power won't be able to place/defeat nearly as many groups as teams with high power.
The current system gives high-power teams a double advantage, higher rewards from the higher tier and higher awards because they can reach highest point threshold.
(2) Matchmaking should be primarily based on monster power. We are a war team, we have a team score of 150k (#88) despite being ranked only ~290 in monster power, at 2.06mil.
We are matched against a team that is #69 in monster power with 3.28mil monster power, over 50% more. I would be very surprised if the outcome of the battle would be even remotely close.
(3) This whole thing with "defensive monsters can't be used to attack" does not work for me. The (lengthy) argument is at the bottom of this post. Why not simply double the amount of teams that can be placed but make all monsters available for attack?
Other feedback:
- Could we please have stats, like for team war? It's impossible to tell who did what, especially if players go against the agreed upon strategy.
- Can we get a preview on the runes in the area screen that lists all placed teams? I found myself inspecting 20 lineups at one point until I found a matchup I liked, as I had used my best monsters already.
- I think the rewards in general should be more shifted towards individual rewards. I see a lot of players sitting back and relaxing, collecting the fruits from the gems that other players spend to revive monsters. So in the end 15 players do the heavy lifting but all players in the team get very similar rewards. Also that gap at place 4 and 16 is rather arbitrary. That should be based not on rank in the team, but on points achieved - give rewards for reaching 1500, 2500, 3500, 4500 points, plus a small bonus for team rank.
- I wonder if the next event will also give out Talany cells? If not, what good are 15 or 25 cells as reward? If yes, what good are those cells anyway? Grind my behind off for 4-6 wars to get one unranked monsters? Nah.
- The rewards for lower tiers are IMO not sufficient. We are in tier 3 and about to be overrun by a much stronger team. Do I really want to go out spending gems left and right just to lift us to 115k, giving 10 extra cells and 7 elementium? Nah, again. No way.
Appendix: on the defense vs. offense, or why I don't want to place monsters on defense at all.
First let's crunch the numbers. Teams that have enough monsters to fill all 600 teams and have ~700 more for atttacks don't need to worry about this. But then, we are a top 100 team and are nowhere near this category, we had only 15 teams placed in some regions.
So, assume we as team can form 30 monster groups for a specific area. Should we (a) place all 30 on defense, (b) 15/15 or (c) all 30 on attack? It's a no brainer to go (c). Here is why.
(a) More points on offense. Those 30 teams on defense will give us 30*150=4500 points. But it also gives our enemy the chance to win 3000 points for defeating us. If we place 0 on defense and keep all 30 for offense, we will get whatever points we get for defeating the opponent plus the bonus points for clearing the region. The bonus points average 6k per region. So if we get 30 wins on offense there we will get 3000 + 6000 = 9000 points.
(b) The attacking team is always favored, as the attacker can always look at the defensive teams and choose a group that matches up well against the defensive monsters. For example, I always choose my monsters in a way that my denier is just a tiny bit faster than the fastest enemy monster. So the chance to win on offense is much higher than the chance to win on defense.
(c) If we don't place on defense, the enemy team will earn less points by beating us there.
Of course, we miss out on points if we have unused monsters in the end. But as the current battlegrounds go, this is unlikely.
Bottom line: Strategically it is much better to hold back most of the monsters (and the best monsters) for attack. But the whole point that makes similar matchups interesting (team wars) is the simple fact that every player will choose the best possible matchup on defense. Battlegrounds will be less interesting if we place only scrap monsters on defense.
So, again, let's use all monsters both on defense and offense. This will make the game much more interesting.
