I wanted to think about my answer to this before I commented because there are some things in this game that feel annoying to me not because they're grindy, but because it's outside my usual genres. Or at least is for the last 10 years or so. I am definately not the guy. So I wanted to try to see my biases.
Also realize 95% of my gametime is on a multi-player server where different people have different goals, and sometimes that competes with World Tier.
There are a few things that feel grindy to me.
Mission only spell components:
One is mission only spell components. Because some of them (I'm looking at you, Earth Essence) usually only pop in one or two/mission and you need eight or better, you spend the entire Tier 4 looking for only missions with that as a prize. This leaves you at the mercy of the RNG or having to hunt down secret after secret hoping the one or two prizes are what you need.
There are two ways I could see reducing this. The first is to make 'seek resources' not be CP missions. The second is allow some secret missions to be 'pick your own prize'. Since I don't really get a choice of what mission it is, I'd have to do whatever came up, even if it's outside my 'favorite', or I could skip it.
Town Building
This has been recently addressed in the patch, so until I see how that flows I don't see a reason to comment. The new pieces and enforcing order/volume are a welcome thing to see.
Maze Rooms and Puzzles
Okay, I get the maze rooms, but when I first started I tried going into everything, now I avoid them like the plague. However, when you're first starting, you get this real feeling of NEEDING to build your enchantment library. Then you spend 4 hours in 3 maze rooms or something equally foolish. Now, I realize the store etc makes this less of an impact, but the maze rooms are still grindy to me.
However, these rooms are primarily used as delays in getting to the REAL grind... puzzle rooms. Alright, I get it's supposed to be a spell usage/aiming challenge. Do they REALLY need 400+ orbs in them? I did one of these once just to see. It took me two hours trying to aim different spells in different ways to figure out what/how/where/when. Also, that's not a puzzle, it's a test of patience. All too often spells 'slip' and hit inner orbs, you're trying to walk a blue/red to the outer corner to just hit one and now you hit 3 instead of two, etc. A 50 orb room wouldn't be TOO bad, then it's just something different to do for 10-20 minutes. At 400 it's a bit much.
and those enchantment comments lead to:
Legendary Enchants
This is a biased annoyance and probably doesn't belong in this list, but I'd like to see some Lieutenant level bosses who drop legendaries in some secret missions. 6 drops/continent when they're procedural seems less then optimal, and I'd like a chance to go after more bosses for better ones without having to switch continents.
Oblivion style world leveling
The last piece that's 'grindy' to me is more of a feeling then anything else. It's the fact that I never get anywhere. Sure, the idea of 'constant challenge' is good, but this game has a 'leveling' feeling as you build bigger spells and whatnot. When are they bigger? They aren't. The only thing they are, ever, is "too small" if you go OL/LT hunting too early. You can never go farm Green Slimes, they grow up with you.
Now, for World Missions matching Tier makes sense, they're the 'challenging' part and the OL's not exactly excited you're coming after him. I'd like to see the old mechanic that I've only seen pictures of in Beta where the tiers 'spread out' from you and if you go back to an 'early area', you're a superman.
However, I realized something while I was pondering that for this... and it's that it will cut early players off from far-reaching areas to get their favorite spells, because they'd be T4/5. That's absolutely no good either. I don't have a solution to the issue, but right now my numbers simply match their new numbers. Yay?
Hm, I actually agree with alot of that.
The whole "choose a reward" thing is a good idea if they were to implement it right. Could get those accursed Sea Essences that way indeed.
The only bit I dont agree with is changing the tier system; I know I sure as heck dont speak for everyone, but part of why I play the game and enjoy it as much as I do is because it's challenging. Way too many games out there are so bloody easy that they barely take effort..... THIS one does. And really, if there's an area where I'd be overpowered for, like, taking hardly any damage and squashing foes in one hit (due to character power, instead of say, difficulty setting)..... it's an area I have absolutely no desire to go to, and if I DO have to go to it, I'm bored before I even enter. I cant focus on easy games whatsoever; never could.
I would like to see the increase in difficulty be a little.... stronger though, as the tiers increase. Enemies get new patterns and such, but their relative damage level usually only increases a little. That's how it seems, anyway.