I want to preface my post by apologizing for the tone and focus, it is difficult to discuss fan ideas in the context of games since these ideas haven’t been implemented and don’t have resources hooked up to see them in action. Not trying to shoot you down or to say Gearbox should get right on your ideas, I just want to add my thoughts.
I think it is healthy for a franchise to acknowledge its tropes and try to bring those concepts forward. The mechanics you call out as on the verge of being cliche, I personally would like to see stick around in some form. Whether that is by bringing back the characters that originally used them, or by making entirely new characters that contain some form of those concepts. As an example, the double shot per trigger pull mechanic has been in every game so far in some form. Mordecai had it first with Gun Crazy, then Zer0 got Tw0 Fang, then Nisha came along with Hell’s Comin’ With Me!. Every time I saw it, I didn’t think, “Oh, how cliche,” I thought, “Oh cool, glad that’s back!”
I think a turret class is essential, but with each iteration I feel they have improved upon the gameplay of it. Roland’s Scorpio was very restrictive and unfocused, you couldn’t reclaim it for CDR and it just kinda sat there and did its thing. Axton’s Sabre Turret came with some crowd control and more advanced positioning, but it didn’t really create gameplay (Double Up was a nice touch though). Then they added Wilhelm’s Wolf and Saint, and they were just about perfect. They did some damage of their own, but they mostly existed to support your efforts. You would work together, having them mark targets so you could go in for the kill. They also brought strong utility for group play. Thematically they were the best a turret class has ever been in Borderlands, and I find myself excited to see what’s next for the soldier archetype in the franchise.
I’m not real clear on the bounds of your third point, does Aurelia fit into this group or is it just Gaige? If it’s both of them, I would say they function very differently. Is it just the thematic you don’t care for? I would tend to agree that it’s nice to see the devs create more unique class fantasy; however, it is difficult for a game in this fantasy genre (futuristic dystopian space western) to break the mold. AI is a big thing in the genre, so of course they want to have robot companions present in the story, not to mention that logically of course we would have robots do everything for us. Humans are lazy and we like our automation, so in a world where robotics technology is advanced enough it wouldn’t make sense for them not to be everywhere, barring story reasons (space racists or a machine uprising). Finally, outside of magic, there really isn’t a better delivery method. How else are you going to create a roving AoE melee threat or an autotargeted flying liquid nitrogen dispenser. If it isn’t robot companions, then they would have to make literally everyone a siren, which to me would be far worse.
The generic buffs are just a part of RPGs, no way to get away from that. If they didn’t have +% damage skills, your guns would be terrible as you fight enemies with more health and you would just end up leaning on actives or procs in your skill tree instead. Imagine if your guns didn’t do more damage with skill ranks, and you could only pick up things like, “Your bullets have a 10/15/20/25/30% chance to release a poison nova that deals 10% of the target’s health.” All of a sudden the gearing process is meaningless as the only thing that matters is mag size and fire rate. I think they have a good spread of damage buffs/active skills/procs/utility/defense in TPS, but opinions may differ.
I agree completely on the stacks point tough, not every character would realistically count kills. It makes sense characterization wise for Aurelia and Nisha, but not for Timothy as an example.
I can’t really speak to your character designs; as I said, without implementation specifics, there’s no way of knowing how they would work out. The humanoid ones sound like they could be compelling, though. Only thing I would say is where does magic fit into the universe? Is it sleight of hand? Is she a Siren? Is it technology-driven? But a blink spell would be fun for juking enemies and possibly jumping through walls to escape enemy fire. I like it!