the thing is about the level system,
yes its fun, but at the end of the game and you gotta grind, guess where you'll be spending a couple hours at?
1 same area. going back and forth, this is the exact same with Souls/weapons/glyphs/skills
The problem isn't the existence of the level system, its the existance of the Grinding aspect that gets very, very old.
Solution is to knock things down a bit in rates so leveling would be morderatly fast and you wont have to spend an hour or 2 for that thing you want.
I remember spending an hour and a half for 1 ghost dancer soul (DoS)
3 hours for a Bloody Mermaid meat (OoE)
and 2 hours for a runesword (SoTN)
I'm not saying just hand it over, I say at most 30 mins should do the trick so you wont mindlessly grind.
Hmm, your argument seems more directed towards the drop rates of the game vs leveling up, but I'll talk about both anyways xD
In regards to base stat leveling up you don't necessarily need to stay in one area to train unless you choose to, and with adjustment to the enemy AIs and their stats (strength, defense, how much exp they drop, etc), then leveling up won't seem so tedious and can seem more natural and progressive. If a game were to be designed with that thought in mind (which is the case for most konami metroidvania's I've seen), then the castle of the game would need an increase in size as so each room's enemy level range is more narrow and grinding won't be as tedious. Not to mention the equipment you will find often help balance out the playing field, or at least they should be strong enough to help against the boss of that area. For as long as the game can be balanced out that way, the leveling up system is still there for those who want it, yet most players can just go through and look for the equipment to balance out their stats against their enemies. Ontop of that, it will come down to the skill of the player to get through each battle; stats isn't the only determining point when fighting bosses and such.
Based on the examples you gave at the bottom, the grinding issue seems to be more apparent with the drop rates of particular items, glyphs, etc. That one I can say that a good number of people will find it tedious to farm for those items (even myself at times). The thing with drops (not including story related/effecting drops), they're completely optional and you can go through the game without it. Of course if you want an edge on your opponents you will need to grind for it, which is why the designers made them hard to get because of how useful they would be. All that said, I don't mind the drop rate being increased a little however (particularly for story related/effecting drops).
Whether the player goes through the game by only leveling up, only gathering equips, or both (which is mostly the case), is entirely up to them. Again, skill will still be the most important factor in every fight you go through. I simply wanted to defend the "base stats" leveling up system, because while the changes may be small per level, they still have an effect on the overall game and gives you feel a sense of accomplishment after killing enough enemies.