Some features, not all of them are good, just a bunch of ideas :
-Being able to customize the range colour of each skill individually with notetags hex colour <rangecolor: #ffffff> same with AoE color etc, if not found, use default (exemple for white magic, black magic etc.)
-Unidirectional range display for some skills (notetag?) : if the game only use 2 grids system, maybe create a system that show attack range only on enemy grid and heal only on ally grid (and put the cursor by default on the "good grid"? (but for some games there is sometimes people who want to heal enemies and attack allies so I think this is not important)
-Tie movement to a gamevariable or MP or TP or add a new movement "bar or points" and as long as you have some movement points, you can move as many times you want in your turn (before using skill or after using skill) (But also adding teleport move type that does not use movement points but mana instead for example)
-Being able to switch places with an ally or enemy (and also why not applying a buff to it), or lift it then throw or teleport it from a to b point (2 selection in one turn)
-Setting traps in enemy camp or glyphs in ally camps, just moving on it inflicts damages or buffs then disappears OR effect apply only while standing on it
-Invisible state, if all allies are invisible, enemies will hit somewhere randomly hoping to hit. Also why not chameleon enemies (but their info must not show when cursor go on their cell)
-Aura states that affect positively/negatively ally or enemy standing next to you while you are standing next to
-Adding state that increase/decrease movement or skill range. (must create a notetag for skills not affected by boosted range or diminished range) (can't go lower than range:1 as a failsafe)
-Charm state that temporary put an enemy inside ally grid and will go back to enemy side when charm state vanish
-Funny AoE, like lines, rows, checkerboard or custom either using an other map or a custom formula either on a json file or read as a notetag inside a skill
(Example x0y0 only hit the center, creating a + AoE would be : something like
<AoE:x0y0,x1y0,x-1y0,x0y1,x0y-1;> (I don't think that's the best way of doing it but it gives full control over AoE)
-Tie AoE to ally or enemy grid and not user position (example a skill that only hits the corners of the enemy grid)
For a boss that hits extremely hard but only at a specific position (example near lava pits) that could bring an interesting mechanic
-Being able to resurrect a dead battler at the position the battler died OR at the emplacement of the resurrect skill?
-PvP over online (yes I know I'm dreaming, even a simple select team against someone who did the same would probably too complex?)
I got a ton of other ideas but that would made the post even harder to digest, so I'll stop there!