My ideas for new character mechanics:

rossmon

Just creating a list of different types of new abilities that could be interesting

Create-a-tank

I can see an interesting characteristic of a character who has passives that add to their match damage, so that you can basically create a tank that doesn't have great active abilities....
example:
4* juggs has headbutt, board shake, and (white cover?) that adds +X to match damage for him for each cover
example, at level 70, having base:
9
41
8
41
37
32

but with covers:
11, 13, 15, 17, 20
43, 45, 47, 49, 52
10, 12, 14, 16, 19
10, 12, 14, 16, 19
39, 41, 43, 45, 48
34, 36, 38, 40, 43

characters that have passives that work like boosts:
Passive>
start match with x ap in each color
start match with 2 ap in (add colors based on covers, kinda like hood's steal.)

Active ability that rotates the board, or a board shake that moves every other row left/right by x tiles>

example

.





the 1st and third shift right 1 tile, 2nd and 4th shift left 1 tile, edges wrap:

> > > > > (loops)
(loops)< < < < <
> > > > > (loops)
(loops)< < < < <

Producing:

Change the world:
swap 2,3,4,5 selected pairs of tiles without making matches,
as in it works like loki, except you can select the tiles. This allows you to set up better cascades from the ability.

a character that has a passive that collects the ap from destroyed tiles when making match 4+ (just if that character is tanking, not all match 4s.)

passive abilities that give a %resistance to various colors. Like:
<Character> is strong against color, and resists x% of damage in this color (higher covers may heal team with a % of the resisted damage)

passive abilities that play off of cascades,
extra damage when reaching 5 combos or more,
extra damage when matching red/green in same (match or entire cascade)

character with a full board refresh ability?

heal tiles?

Poison ability? a countdown tile that 'attaches' to targeted opponent and deals x damage each turn, even if they go invisible or move behind. This ability ignores protect tiles.

I may add more later....

Unknown

I like the idea of adding poison or burn abilities.