Just tried out one of the simulators for summoning- in ten minutes worth of summoning and spending a theoretical £800+, I didn't get any of the three or four characters I was interested in. These kind of odds make me not even interested in spending the smallest amount of money as it's just incredibly unlikely to get me something of use. I think the way forward with these games (for me) is to just accept that I need to make the best teams I can out of what RNGesus blesses me with, as actively hunting for something seems pointless.
The #1 advice when it comes to these games is to always pull for banners and never chase rare as fuck units. You're not going to win against the house 95% of the time.
You favorite unit is stuck with 3 other scrub tiers sharing the same color? Don't pull
Is a great unit stuck in a banner 3 three good units, that while not broken as hell, will remain useful for years to come? Go right ahead.
Unless you're a whale that doesn't mind dropping $1000 a week, your main goal is to always minimize your losses. That ensures you're not gonna be in a bad spot if you didn't get what you were looking for in a pull.
This is exactly what I'm looking for in new units - skills that no one else has because, as you say, as the meta shifts different skills become more valuable.
I think the main issue is that people are coming into this game with the wrong mindset, especially brand new players to gacha. In main series Fire Emblem, speed has always been one of the best attributes so units tend to get judge on that first and foremost. As a result, once you know the enemy stats (can they double character A?), map layouts (Is character B useless in a game where defend missions are common), and promotion/story structure (How early can I promote Character C compared to D), people can easily theorize who the best characters are,
However, Fire Emblem is an static game. Once you know who the best is, that's it. For example, Odin will never be considered "good" in Conquest no matter how much people believe the opposite. Everything in those games have been analyzed to hell and back these days, so it's easy to declare people top tier and the like.
Gacha on the other hand, changes... a lot. I can assure everyone here that FEH will not be the same game we're playing right now, 6 months from now. For all we know, the meta could eventually revolve around 4 tanks, which will make speed, the barometer that has been used for ages in this series, absolutely useless if units aren't able to make a dent. As a result, units like Ephraim will gradually rise in value because they provide the tools that allows those units to do their job. Support has always been invaluable in gacha because is a function that's difficult to replace.
Also, most people on Reddit and other communities don't have any idea what they're talking about, especially after new units get added, so don't listen to them. Real in-depth analyses from knowledgeable people usually doesn't happen in less than two hours.