If your biggest complaint so far is that the book doesn't have enough mustaches, it looks like it's going to be a great book
This is actually one of those things I feel like we should examine a little more deeply and not dismiss out of hand.
WotC has consistently given short shrift to world building since the start of 5E. Their adventures and settings are shallow. I like to refer to 5E as the "MCU Edition" because it is popular and fun and cool, but shallow and, frankly, it's best not to think too hard about it.
The "lol why are you worried about mustaches" attitude is a pretty succinct distillation of the the MCU attitude. Who cares? It's just facial hair?
But here's the thing: little details are the key to good worldbuilding. Whether this culture wears long mustaches (like the Celts; it didn't appear out of nowhere) or this culture has a schism between the two kinds of elves is important stuff. It matters, from the perspective of building a world that feels real and complete and deep. Dismissing it out of hand reveals an "MCU" attitude that amounts to "shut up and get on with the adventure."
Which is fine as far as it goes, but some people want more than that. Some people want detailed world building even if those details aren't focused on combat bonuses or class abilities or other mechanical bits.
What's weird is that there is no problem with keeping mustaches as a cultural aspect of the Knights of Solamnia. It doesn't do anything to make them bad or unpalatable to modern audiences. But they still just ignored it. It wasn't even on their radar. You can tell by the art. That should tell you how much they care about Dragonlance in general. They don't care about its nuances or particulars. It's just another nostalgic cow to be milked to death. It is an IP meant to be marketed in such a way as to extract as much income from both older and new fans as possible with no regard tow hat it might have meant at some time.
Which is fine. WotC is a business. They should want to sell books. But by the same token when older fans see that it is a shallow cash grab, we shouldn't feel bad about not buying these things. They aren't for us, even if they try and convince us otherwise with nostalgic names.
And to be clear, I am not suggesting that new or old fans who don't care about how WotC is treating these old properties are wrong. They should absolutely enjoy the things they enjoy and support those things by buying them. If WotC is making stuff you love, by all means, buy it and support it and evangelize it, regardless of it nostalgic cred.
But if they aren't? Don't. Don't buy things just because it has a brand on it you once loved. Don't reward them for doing something wrong to a thing you loved. Don't be so desperate for validation of your formative brands.
The lackof mustaches doesn't mean Dragonlance is bad. But it is a hint, a suggestion, that WotC hasn't really even looked at what they were re=-creating beyond even the most basic level. Their concern is about broad, shallow features that appeal to the widest audiences, without concern about anything that came before or detailed worldbuilding that (although arbitrary) gives a sense of texture to the world. WotC doesn't care about the depth of Dragonlance because they don't expect you to care about Dragonlance six months from now. And that goes for every world they produce.