I played on Expert and found the game too easy actually, I never even parried, just dodged. But you are still lying because the things you said are just flatout wrong,
only agi and luck are good
VIG/DEF matter early, then only weapon scaling stat matters most
most of your damage from level ups
Who the fuck isn't upgrading their weapon regularly? That's a no brainer to use all your upgrade material upgrading your weapon, but a ton of damage comes from weaknesses, using high damage multi-hit attacks, lumina, weapon scaling, and burn stacking.
Not once did I see an enemy and think “that is sick”.
Tons of really creative and interesting bosses, especially by JRPG standards where most enemies look like the digimon reject pile
Not once in this game did I have to use a “unique strategy” to beat an encounter.
There are tons of gimmick fights that require a specific strategy (lampmaster, the parry bosses, mime breaking, etc.)
parry becomes king since you get mana back
There's not even fucking mana in the game. Dodge is better unless you know their attacks inside and out, since it's way more forgiving and you can use a ton of lumina to get just as much advantages from dodging/perfect dodging
If synergy refers to only using a couple of moves to apply a shit effect I guess it applies.
synergy with Maelle stances, marks, Lune stain usage, Monoco wheel, Sciel fortune, different buffs, etc.
The “trick” is just parry and spam your highest dps move because the game discourages any other play style
wow, everything seems simple when you just simplify it down to "avoid enemy damage, deal damage XD"
There are tons of character combinations, skill combinations, different weapons, lumina/pictos, learning specific gimmicks/weaknesses of bosses, and even just removing all strategy from the equation (of which there is a lot), the dodging/parrying is a game all on its own trying to learn all the different moves and timings of different enemies/bosses.