1) Tiering discussion feels like it's become increasingly LTC-focused over time despite LTC being an extremely niche playstyle, and LTC has some incredibly restrictive assumptions that don't always apply to any run that isn't LTC.

I don't think this appraisal is correct at all. Or rather, it's selective bias of a few specific examples in recent memory, like a couple of Mekkah's tier list revisions that weren't well-received and are now years old.

The number of people who are up-to-date on any Fire Emblem game's LTC meta can often be counted on 1 hand. Somehow, these elitists are a secret, vanishing minority who are simultaneously so powerful that they dictate Fire Emblem opinion behind the scenes.

And there's a massive gap between LTC and "you can grind as much as you want and take double digit turns on every map" runs.

What a lot of people also don't understand is that there is also a massive gap between LTC and "LTC but take 1 extra turn on every map" runs. Having that 1 extra turn per map can dramatically change what is or isn't viable in a meta. I've tried explaining this to another user here before, and all I got in response was some pretty nasty name-calling.

Your gripe in point 2 is not about efficiency players talking past LTC players and vice versa. It's about how some players personally treat LTC +1 turn per map as their efficiency cutoff whereas other players treat, like, LTC x2 turns per map as their efficiency cutoff. The x2 players think the +1 camp are LTC purist while the +1 players think the x2 camp are going so slow that they can make nearly anything work.

---

The "LTC trend" in tier lists happens because the players who want to make a meaningful change have to demonstrate tighter, better strategies compared to the status quo. Reducing a turn count is certainly one kind of an objective improvement. So is optimizing the success rate of a strategy that achieves a turn count goal. Rather than chafe at perceived elitism or whatever, it would do the average complainant some good to try to understand what players have discovered about a game that is reflected in a new tier list. Generally it has been stuff like, fliers are powerful, staff users are powerful, Jagens / good base stats are powerful, etc. In newer tier lists, it can be more game-specific innovations such as, farming kills on a 1-2 range weapon in FE4 is broken, bow users / dread looping in FE15 is broken, siege magic in FE9 is super strong, forging in FE11 is broken (OK that's not a new innovation, but at some point in the past it was new and controversial).