>>725604914 (OP)
>overworld encounters, timed inputs
These are suggestions made by normalfags who never liked JRPGs and can safely be ignored. The real issues with JRPGs are repetition and lack of customization.
For example if you took any Final Fantasy or Dragon Quest, increased the encounter rate by x4 and reduced EXP gain to 25%, everyone would call them shitty grindy games. Likewise, a lot of JRPGs could be improved by reducing the encounter rate and increasing EXP gain to make them less repetitive. This isn't the 90's anymore when long-ass games were a selling point, nowadays people have too much shit vying for their attention and the lack of excessive padding is appreciated by everybody.
The other big one is lack of variety, options, or personalization, since if the combat itself isn't engaging the game has already failed. Is your party composed of preset story characters with preset stats, skills, etc or it composed of a custom mix of characters with stats and skills chosen and allocated by you? Is the skill selection meaningful and varied, or just damage / more damage / lots of damage? Etc. Enemy encounters are important too--they need to be varied enough to meaningfully change the way you approach them. If you can bulldoze every encounter with the same skills / gameplan, the game has failed.
While technically not a JRPG series, Etrian Odyssey has my favorite turn-based combat out of anything I've played. The party customization is deep, the enemy encounters are varied, and the level progression is quick enough to hold my interest for 60+ hours each game, which is a feat.