Older Beast Tribes
Having similar feelings with friends joining the game, heck I even joined about a year ago, but my partner was going through the arr beast tribes for the dyes, materials, mounts, minions, and furnishings that are exclusive and was a bit sad. He was doing many of them at once at first for optimization until you increase influence enough to only really be able to focus on one or two. I personally have not done any of them other than the Ixal's just because it is on my to do list and kind of started backwards with the shadowbringer ones. Still need to unlock the moogles.
They were kind of sad at some point that it had taken so much time to gain influence with them he forgot some of the story bits until refreshing his memory because the grind was putting him to sleep. You just kind of go through the motions for the ARR beast tribes at some point after a while. He noticed when getting to the HW ones the time it took for influence was way shorter and it was easier to maintain story information without looking up a summery refresh. It also allowed for him to be more invested though he did say he adored the ARR ones, recommending I do them for the precious stories. It is on my long to do list.
Older Custom Delivery NPCs
I went a bit slow through the story so by the time I made it to shadowbringers the only two I had left was dapper kitty boy and the princess under water I kind of left hanging and still need to do the side quests for. Partner was a bit sad at the time of just getting into ishgard with his impossibly almost level 80 leatherworker. (Still have no clue that happened, I think he was very dedicated and instead of going through the story power leveled with turn ins each day.) It was even kind of sad someone said they were giving minions to sprouts and they told him your not a sprout. He was only playing for a few months >.< luckily he didn't care about getting a minion and wanted to tell them keep up the good work. Still a bit sad with how fast you could level something if you grind and put your mind to it.
I digress, he made it to idyllshire and I know this will happen to many friends who are catching up, but you only really have access to one at the start leaving you with 6 extra delivery mission allotments for the week. A bit of a different issue than mentioned but still one that is a bit weird. I know you need to do the side quests some of which are random as heck like Adkiragh. It is kind of depressing knowing many custom deliveries on a timer are being left undone because you can not physically unlock them yet and can't do more than 6 per person.
Can we at the very least get blue plus quests next to these along with the beast tribes moogles and namazu. The quest line I think at one point had a blue plus than it didn't than it did again and continued in a random area. I know it is kind of cool stumbling upon these things when going about your journey but gosh I need to follow a guild to find the moogle quest line. My partner stumbled upon it as he was doing every moogle quest in the churning mist. I knew it existed but I would have needed a guide to find which one it was if I wished to focus on them first.
Doman Enclave
I swore something else was done like this already so it shouldn't be hard to just be allowed to go through the quests without the road block. Didn't the firmament do this as it progressed and now you kind of get a bulk set of quests. I just did the bulk set of quests but it seemed like it was highlighting all of the changes quickly which isn't a bad thing but did feel as if they use to be in installments.
They could do the same thing with doma. I do however recommend any new player save their coin bags for it because if you can donate all of your stuff to further it along quickly you might be stuck waiting if you have nothing to donate. I have warned many to start doing this when they know they will go through to stormblood so they are prepared and get the most out of the extra gil you get due to value being increased when giving them your bags of allagan silver pieces, bronze, and whatnot. It really ads up if you have been saving quest rewards for it.