Tectuktitlay
Explorer
I would like to see a nonspellcaster class. (maybe a 3rd-caster archetype) We already have tons of spellcasters in 5E, I would like to see more noncaster options.
That's one reason I specifically wish to see artificer. I don't want artificer to cast spells. I would prefer it if they actually had to take levels in some caster class to truly cast spells. Instead, making various items depending on the subclass would be new and novel. Here is a class that makes things others can use, and probably that the creator can use to better effect than other people. They probably have time limits, and there's some sort of limit on how many they can have made at a time, but rather than being a class that primarily enhances themselves or directly effects enemies, they invest their character resources on making various disposable objects for folks to use.
It's also why I place a poisoner archetype in the artificer. Perhaps with options within the subclass that lean rogue, making them a variant assassin that relies on a mechanic other than sneak attack to deal heavy single-target damage, only with extra effects tossed in (like the poisoned condition, paralyzed, etc).
After reading the thread, and contemplating what would be the least like every other class out there, a major archetype that creates objects with various uses fits the bill.
Other than that, a class that focuses on having one or more companions/allies would be it. Basically, where D&D has previously gone for either summoner casters, or for druids and rangers with an animal companion, have an entire mechanical chassis based on having one potent companion, or a number of much less powerful companions, running around. Your abilities enhance them, and enhance how well you coordinate with them. Unlike similar builds of old, the spellcasting portion is removed entirely, giving more design space freedom to fill that gap with something else. Most likely something else unique to each subclass.
For example, an beast lord subclass would have a potent single combat-oriented animal companion, with perhaps a couple of familiar-like non-combatants to supplement it, and a suite of abilities that give you bonuses to you and your allies for using the animal companion for teamwork.
A psionic astral construct creator, on the other hand, would have some sort of companion that has a utility-belt like suite of abilities allowing you to tailor it on the fly to your current needs. Sometimes, it might be better to see through it. Other times, flying might be better. Others, grappling. And so on.
An engineer-type might just have a golem, that they can build bigger and badder as time goes on, focusing most of their combat ability not on themselves, but on this arcane construct pet that does their bidding.
A necromancer might not have a single companion at all, but simply be able to regularly summon small swarms of disposable companions much less powerful, but that engage in wars of attrition until they collapse as their necromantic energy is exhausted.
But the key would be, they don't do nearly as much with themselves, most of their mechanical design space is focused on these extensions of themselves, while they remain relatively the same for the most part. Obviously they'd have some growth as well, but it would be less noticeable than other classes.
Since the core mechanic is the same for these various types of characters, even though they might each play radically different, as with spellcasters they are build on the same basic class chassis.