There's something I keep listening on my guild or reddit that keeps me intrigued and unease, people keep saying that you only need a SDD team and a Ranger Square (4 CRIT Rangers) to play VF. Well, the bad part about this is: they are partially right most of the time, having just those squads you can clear most content, just get the event hero and you're good.
BUT! Valiant Force was not meant to be played that way, and well, we all know that, so I wanna suggest something to make squad diversity more interesting with the introduction of Formation Bonus to be used both on PVE and PVP content.
The concept is, incentive new squads by making diversity rewarding, here by adding bonus to your heroes so you want to try new things.
How does it work:
Simple, you go to squad menu and start to add heroes, when you create a combination it will show to you on screen, those combinations can be formed by 2, 3 or even 5 heroes (full squad), they are:

The double hero formations are based on 2 heroes of the same class being used together, jus by placing them in your squad you will get the bonus stats for all heroes in your squad + the formation skill.
Important Note: You can't use the same formation 2 times, so if you use 4 Ranger or 4 Guardians in your squad you will only receive one formation bonus based on this combination.

The Triple Hero Formations are based on the original Back Row or Front Row classes.
Important Note: If you use 2 same Class heroes + 2 others, this formation will be the one active.
Example: 2 Healers + 1 Mystic + 1 Ranger - This will not make the Double Healer formation active, as no hero can be in more than one formation, so the resulting bonus will be: 1000 HP + 500 DEF + 500 MAG.

The Full Hero Formations are based on using 5 different classes on your squad, making it more diverse.
Important Note: You can't use the Triple Formation + Full Formation together, if you match two combinations only the full formation bonus will be active
I think that this system encourages diversity and more strategic options for squad build without nerfing what's being used and would be relativity easy to implement if the devs wants to
Obs. I could think of different bonuses based on combinations but the more diverse and complicated more balance work would be needed, so I choose the simple option so it could be implemented without much trouble.
Feedback is appreciated!