I'm not entirely sure if this was meant to become the suggestions thread as opposed to a little guide but hey! A couple of things have kinda bothered me, or if anything, nuances so far.
Familiar Mechanics
As it stands, familiars are rapidly becoming a waste of time. The problem is mostly caused by the fact it's high effort for low trade off. When you have a couple, especially low "level", familiars, it's fine. The time taken quickly pays back with a chest. However when you get to the later levels of (love?/familiarity?/I'm not sure how to term it haha), it rapidly becomes tedious and frankly, boring.
Some people have suggested a page specifically for familiars (So long as they're in the company of a dragon) to save going to a dragon, click the heart, click okay, then navigate to another dragon you have set up (I've arranged all mine in a group so you can just click right). That's a lot of clicks and time, for what can just amount to just 300 treasure if you have 10 at inquisitive status. Something a lot of players know is much easier to grind out from gathering, the Colosseum, and the fairground.
Alternatively, if you want to stick to the current method, then there needs to be more reason to actually do it. Once you hit "relaxed", the time until that next treasure chest becomes quite a while! I'm not saying have relaxed/inquisitive familiars give random chests between levelling up, nono. Nothing like that. But perhaps randomly once a day once they hit relaxed or inquisitive they randomly give you an item? Maybe a piece of food, or something you'd get from gathering. Maybe even rarely a piece of apparel.
From looking up some guides, this would certainly be a nice mechanic for when you've maxed out your friendship with a familiar.
In basics: Currently it's very tedious to actually spend 89 days (According to this guide:
http://flightrising.com/main.php?board=gde&id=987700&p=mb) clicking a heart for a familiar, let alone multiple familiar.
Phew I rambled a lot there sorry. Secondly...
Auction House: Battle Items
It's faaaaaaaar too cluttered and a pain to search for something you might want. In addition to the elemental choices, you should have an option dedicated to selecting the type of item you want, be it a item or stone
types (Battle Item/Energy Stone♦/Ability Stone â—/Argument Stone â– /Accessory Stone â–¼)