So I'm a relatively new player and just thought I'd offer a perspective that, while some did do their best to consider when speculating the ins and outs of the implementation of natural Diamonds both in the mechanics as well as falling into the hands of a new players, hasn't been spoken on here by one of those players. There's a TL;DR for anyone who hates reading, though by itself isn't gonna offer you anything of much substance.
I'd call myself a veteran when it comes to gacha style mobile games and understand all of the concerns and viewpoints already discussed here.
Typically speaking, I usually have abysmal luck with draws in even games with very generous odds, so about 0.001 seconds after seeing that 0.5% draw rate I ceased expecting that to ever happen no matter how long I played because I'm a F2P player.
Top that with the fact that you certainly do not earn theonite at as fast of a rate as you do in alot of other games (which is just to make players not dip out after a poor first few draws until they don't feel like losing their invested time by "rerolling") and it was clear that saving up for a 10+1 pull was gonna mean sticking with whatever you did have and hoping it wasn't so terrible you were progress blocked until then, I really had no expectations.
Well as fate would have it, turns out this game among the countless I've delved into was the one that I was blessed, despite the unbelievable odds- and I got it from a premiere summon that was a reward for a low level story mission of all things.
I was only acc level 5 or something really absurd, and for whatever degree I'd have been speechless, you can be assured I was even moreso to get it so early and so unexpectedly. I had already gathered that due to the nature of the game that evolution was not intended to be quite so simple to achieve despite having familiar mechanics, and as with all gacha style games some units are simply '"god tier" and some are simply garbo, so the joy I got from knowing that if I never got a lucky draw again I could at least find solace in that one was unrivaled. I got CC Filia, which from what I've read has yet to receive a particularly solid evaluation on this thread other than the same as my own speculation that since she has so many abilities with several hits, it seemed potentially powerful.
As someone with alot of background in these games, I wont lie. I was expecting this to mean things would be pretty easy mode for a good long while since other games with this mechanic often work that way, which is why rerolls are so common. I played Brave Frontier years ago and despite being a vet who put sooooo much time and effort into getting the team I was proud of, I got progress blocked in the campaign because that game is the overlord of powercreep. Anybody who's played it knows this. It was INCREDIBLY infuriating to see my baby raised units who at one time were top tier just get utterly drowned out by teams of 5 of the same currently most broken unit from P2W. It was even more upsetting for a friend who literally abandoned the game at level 3, returned and collected a bunch of event rewards, and proceeded to draw 4 OP units that he was able to bring up to be stronger than my own team with a bunch of freebie evo and level materials in literal hours. I quit the game at that moment, I was disgusted.
As all of you would already know, this game is not like that. I love this game for that reason. Did I practically s*** myself when I saw the node costs? Rofl without question. But I treasured that Filia (still do) so much because for once I was actually on the other end of the spectrum, as I've never been the player who got that kinda beginners luck in any form. At first I dumped everything into her because all of my other draws for a good while literally couldn't have been worse- I checked the tier list after a fair while of playing to discover all but about 2 where absolute bottom tier, with the other two being just 1 notch up. With the rate I was going, honestly if I didn't have that Filia I can't tell you I'd have been playing for a super long time if things kept up because I didn't want to spend literally 2 years getting the best of what I was given to their max and it just not being enough.
Having her taught me alot though, truly. For one, I learned that as others have said, stats aren't everything. The SA's matter a great deal, but on the flip side SA's aren't everything either, there are a whole lot of factors in what makes a fighter for you or not. Some of my units I was genuinely surprised at their standing on the tier list because I thought they were really good since I had great success with them and even enjoyed playing them more than Filia by a great margin, like my Understudy Cerebella (LOL) and later Dead Heat Squiggly. I love some squiggly :3
But, I also learned the value of a lower tier fighter in the resources too. After a point I wasn't able to get a lot of play time in because if Filia was sapped on energy then I couldn't do a whole lot. Coins were scarce in the numbers I needed for her (lol plus a diamond key with gold is 1 mil if I did get her upgraded, idek with rift coins) and I inevitably had to spend coins on others who's numbers were so incredibly small next to Filia it felt borderline disrespectful to her not to put that 30k into a node even if it was only gonna be a 2% increase and all of my skillpoints.
When those fighters starting breaking into a sharper curve, getting all of their potential unlocked, and sporting a row of killer moves, my feelings changed.
Then I got my first silver (Bloody Valentine Eliza) and I was finally understanding the curve of the game when she began creeping on my lvl 30 bronze at just level 13. Filia was still Queen Stat Stick, and I loved having her for it, but the feeling of fighting with a fleshed out fighter vs someone who barely has a 3rd move slot and a stunted combo juggle is so much more gratifying. I'm still thankful for the luck to have drawn her, and definitely look forward to when I can afford letting her finally shine the way she's supposed to. But no way I can bring myself to drop so much of my resources on her when I could get 3x or more the amount on Bad Ms Frosty instead, and give my arsenal all that much more firepower and versatility. As a result of having her, I learned alot about the game, the value of respective fighters beyond "shiny and big numbers", and ultimately didn't give up on a fantastic game that rewards time invested and skills refined by the player. Now if I could just get anything besides Nunsense Double....
So all in all, I get you guys' side of things no doubt. In your position I'd be just as upset at the prospect of natural Diamonds walking all over my accomplishments. At the end of the day though, I believe the devs handled this quite well and in my personal experience it served as a positive catalyst for my playing experience. I hope maybe some of this offers anything of value to whoever bothers reading it.
TL;DR- I got lucky early on with a natural Diamond and it kept me playing, taught me stuffs, and allowed me to appreciate a game that I otherwise potentially wouldn't have.