There are several things that really bother me about the way Zenimax has handled certain aspects of this game. I'll go over a few of them in detail here.
1. Monster sets and motif pages:
I'm going to be honest. Head and Shoulder motif pages of all styles, no matter what style and armor type they are or how they look, are completely useless. Why? Because any competent player knows not to use anything other than a monster set for their head and shoulders. This is a huge problem that only grows the more motifs are added to the game, adding more useless head and shoulder pages.
My solution for this problem: Make the monster sets appear in more pieces than head and shoulder so players can choose to use those instead, and possibly gain customization of their head and shoulder pieces. I would recommend the belt and shoes, as both of those are the smallest pieces. In the case of robe-wearers, the shoes and pants are actually completely hidden, so that would be another optimal choice. To prevent people from running multiple sets, Zenimax can implement a system that will prevent any more monster set pieces from being equipped after the first two.
2. Armor appearance, dropped sets vs crafted sets, and lack of customization:
Tying into the above point about the head and shoulder pages being useless due to the monster sets existing, in reality almost every single motif page is useless because certain dropped sets are so much stronger than most crafted sets for most classes/playstyles. This is a major problem, because you cannot customize the appearance of any dropped item. The only way to have any real control over how you look when you want to actually be effective is to use a costume. As time has gone on, crafting has become more and more obsolete and pointless.
My suggestion for how to fix this: Give us some kind of interface (I'd imagine it would be like the dying interface, and then a dropdown list when you click on the spot for shield, for instance) for picking an item in our possession (your character's inventory or items in your bank) to copy the appearance of as a costume set, including weapons. Give us maybe one costume slot for free and make each additional one cost crowns, so that realistically Zenimax won't be shooting themselves in the foot by reducing their crown costume sales too much. This would solve just about every customization problem the game has.
It would allow guilds to design a uniform every member could put on and take off in an instant for guild activities/representation. (guild tabards are honestly a bad joke at this point)
It would allow people to use whatever set pieces they want, dropped or crafted, and continue to look exactly how they choose to look. If I wanted to use Shadowrend's helmet (because badass dinosaur), but don't want to actually run such a useless set, I'm plain out of luck as it stands right now, but with this new personalization system I could wear the helmet without completely gimping my character.
It would restore value to all of the game's motif pages as people would actually be able to use all of them for their appearance without making their character weaker due to crafted sets generally being obsolete.
3. Guild store motif/recipe/furnishing blueprint hunting.
Why after all of this time do we still not have a filter in guild stores to cut all motifs, recipes, and blueprints we have already learned from the search results? This is such an obviously-needed function that I'm amazed we still don't have it. Nobody needs to buy a motif they have already learned unless they're hunting for big bargains to flip later, and being unable to sort those learned items out, our interface and browsing experience looking for new items is slowed down to a crawl. The way it is right now, even as someone who has trained their eyes and brain to be able to process moving through the motif list at fullscroll speed (looking only at the line of text that changes when a motif is learned/unlearned and stopping when I see the line change), it can take me upwards of 10 minutes sometimes to get through one guild trader's list (I only shop at major traders that have pages and pages of stuff). If this sorting filter were to be added, I could go into a trader, search for new motifs only, and be done in just a minute or two depending on my decisions and move on with my life. I can't be the only one who desperately wants this filter to be a thing.