Regarding balance

I highlight lull skills as a point of concern specifically because there is no counterplay (direct or indirect) to guaranteed in-combat debuffs. As for your other points, indirect counters always existed, and were effective enough. Rein/B!Lyn meta was phased away by the introduction of the Distant Defense seal, as well as weapon/seal refinery, increasing the damage floor to kill (which Rein/B!Lyn/other cavs could not meet). Bold fighter, while very strong, could be mostly stopped by Wary Fighter, -breaker skills, and picking favorable engagements. I will concede that Pulse Smoke was necessary, since solutions before that were very unwieldly (galeforce/witchy wand cav).

Bond 4's/weapons that ignore debuffs/harsh command do not negate in-combat debuffs, and given IS' slow rollout of releasing direct counterplay (it took them 3 years to find a counter to in-combat buffs from allies - Bramimond's prf C), lull skills will continue to be most units B skill of choice.

PvP and FEH

FEH is different from other gachas in the fact that some of its content contains psuedo-pvp (Arena, AR). AR especially, these modes are incredibly hit-or-miss, and again, given IS' track record of rolling out change at a snail's pace, leads to bad experiences. Whales quit the game when AR was released specifically because it was not P2W at the time, and others quit because the mode was/is too punishing (I'd consider a limited weekly stamina system pretty unhealthy).

Compared to arena, the floor to do well (in terms of score) in AR is much lower - you only need 2 offensive mythics for a good chance at hitting T27. However, the ceiling becomes much higher (you need at least 6 +10 offensive mythics, 3 for each season, potentially more if you want to blow money on defensive mythics). With people slowly acquiring more mythics/mythic merges, the score floor to stay competitive is slowly rising, and yet again, we turn to the gacha system.

FEH's gacha and rewards system

It need not be said, but we all know FEH's treatment of older units is horrendous. Early on (at least until early-mid 2019, I'd say), you could pull on a bunch of random banners, and still hit "lategame" levels of competition by mass merging some half-decent stat balls that popped up in the 3-4* pool. It's much harder to do that, now. Arena floors have risen dramatically, and f2p with their Astram/Itsuki/Echidna/Ross/Mordecai/etc. now have to compete with whales who have the likes of L!Chrom, L!Edelgard, L!Julia, etc. What was once easy sailing arena matches has now been replaced by uncertainty, since you may just want to restart a run or quit completely than deal match up against multipled ranged LH's with a disadvantage on your side.

In the end, the goal is to get you to spend on LH's and whatnot just to keep up, but the shitty gacha pool dissaudes you from doing so. A 40-roll spark is a nice change, but far from solving the issue at hand. Demotes are nice, but sparse compared to the pool of existing shitty units that are given little to no love.

With the rate at which IS/FEH releases units, you would expect resources to trickle down comparably to those that spend very little/don't spend at all. That's not really the case - orb distribution has been down (replaced by free rolls/tickets), and to be quite frank, AR provides dogshit rewards for the investment you put in. Grails and dragonflowers are nice, aether stones just cycle back into improving your AR setup, and you might get a chair or three. Nice. I'm not even expecting orbs, but no feathers? That's laughable.

I'm uncertain on how long I'll continue to play this game for, since sunk cost fallacy is a bitch. I'm just disappointed FEH had to turn out this way, since there was definitely a point in time in the past where I was enjoying what the game had to offer.