Because I honestly really loved this game, I'll add my two cents to this debate.
First of all, the game is good and has a balanced combat that honestly becomes easy to manage on the Normal difficulty. It has a number of tools and tricks that make for a comfortable gameplay loop that allows you to grind forever when you have good efficiency. Additionally, there is no actual time limit, so you can indeed spend quite a bit of time and essentially grind forever if you feel like it. This is especially true if you pay the interest with Ren's body, which I honestly recommend in the first run of the game, to have less pressure in terms of finances.
However.
It's true that the game has some flaws. The big one is that the skill-tree isn't obvious, and so you have no way of knowing what you're getting into as you invest in various skills. Regen is available for all characters if you invest in the appropriate passive, including for health, which makes self-sustain without using consumables entirely possible. Additionally, nun-girl has a passive that heals after combat, and Ren has a passive that heals the entire party by a small amount every turn. I don't remember which skill lines granted you those skills, because it's been ages since I did all my playthroughs for this game, but I know they're there.
The other issue is that guns are, for the most part, a trap. Because a number of bosses and units are downright immune. This means that investing in the skills for guns is usually a waste. The only exception to this is the sniper skills of agent boy. With the best sniper-riffle in the game, that guy can do some serious damage to the few enemies that are genuinely weak to physical damage... which ironically are generally the enemies that are resistant to both of Ren's main elements in her spells. Additionally, the government supply skill grants a lot of utility without spending a single dime... and of course, you CAN sell those supplies to the black market for some spare change if you really need too.
Basically, the biggest issue the game has is that it doesn't have a proper skill tree, so you know what you're working towards. However, that's nothing that can't be solved with a little save scumming and some dedicated grinding.
