For reference, here is my background coming into Cosmic Exploration: Historically, a very casual PvE player, huge housing nerd, and a bit of a DoL main (though haven't really gotten into fishing). I haven't played much this expansion and only recently finished up the MSQ and got all of my DoH and DoL other than fishing to low 90s. I spent an *unreasonable* amount of time in the Diadem, thoroughly enjoying optimizing my gathering routes, GP and cordial usage, and determining what to gather for the best gil return on my time. I've been super excited to get into Cosmic Exploration.
The good:
DoH progression feels amazing. I've mainly been a macro crafter in the past, but the design and variety of the recipes makes manually crafting things feel really good with a really pleasant level of skill expression. The mech events are somewhat repetitive but fun and a great way to mix things up for the buff. The red alert events are enjoyable and rewarding once I figured out that there are two zones for the alerts.
The bad:
DoL just feels bad. This does not feel like FFXIV gathering at all. There is no way to engage with the content as a DoL without time trials? Seriously? I was extremely crestfallen when I discovered there were no gathering nodes outside of missions. No timed nodes either. Cordial chugging feels absolutely mandatory and there is zero skill expression. I get that the devs probably didn't want Cosmic Exploration to have a major impact on the economy so there is no resource trading, but they seriously couldn't have added a casual go collect 100 of x and 150 of y research missions without time trials? Or at the very least make the time trial missions refill your GP after you turn them in? There are absolutely some that are going to enjoy the time trial style missions, but (admittedly anecdotally) every gatherer I've talked to is really unhappy with how gathering has been implemented in Cosmic Exploration.