I think one thing that makes Spider-Man's whole world of characters so great and rich is that in the comics there is a great balance of joke tier, low tier, mid tier and high tier villains. It would be awfully boring if Marvel tried to make every single villain come off as some big deal.
Looking at Spider-Man's lore as a whole, even the joke and low tier villains serve the big picture in a big way by giving it variety, personality and a sense of realism which makes the whole world of Spider-Man's feel organic and mirroring the real world. There is a purpose of a villain not being "great".
A villain being joke- or low tier doesn't mean he's not well written or likeable. What seperates them from the rest is that they don't cause too much trouble in Spider-Man's or Peter Parker's life. They're mostly easy for him to take out and they make for some laid back and fun pages. Once in a while they have great character moments and use their abilities more to their potential, but it's more rare than of the villains of higher tiers.
To talk about The Spot as an example. Yes, he has some cool powers. But part of him is also that he doesn't use his powers to their full potential. It's like the real world - there are lots of people with skills they don't use to their full potential. There are also people in the real world who desperately try too much for their own good to do things they simply aren't skilled enough to do.
That's not to say the comics are or should be static. Kraven is a great example of a villain rising in ranks and I think a lot of people would say he's high tier after Kraven's Last Hunt. Now there are also lots of people who'd love to see him on the big screen. Tombstone in Spectacular Spider-Man is another example.
So, in the comics there needs to be a balance of bad and good villains to make the world richer and more real. Trying too hard to up the ante with every villain could actually hurt more than help.
The films are obviously different though. There won't be time to show too much of these joke or low tier villains on film. The stakes need to be high in about two hours each or else the films will feel like a waste of time. I simply don't see any room for a villain like The Spot when there are so many other villains who are better and have much more potential. The comics could do a "Kraven's Last Hunt" on The Spot (though very unlikely), but a film is not the place for that.
What about Iron Man, Ant-Man and so on? Well, those movie villains aren't nearly on the same level as should be expected from a Spider-Man villain. Spider-Man has arguably the best rogues gallery alongside Batman and Superman (perhaps X-Men). His villains are some of the most famous and familiar out there. It would be stupid to chose to instead spend time and energy on an obscure and lesser villain.
That's not to say that the films can't improve on villains (I think they should). But the villains they improve on need to be the familiar and famous ones because they also have the most potential. Vulture is an example of a villain who I think could carry a film if improved on slightly. He's a cold and old villain who I think would fit great to be calculating and "old man smart". Looking down on someone like Spider-Man for being "young and easily fooled". Being so cold as it makes you wonder if he has any sense of empathy at all. That could make for a great movie villain.
Shocker is a low tier villain who could work great in a film as a hired gun in favour of someone like The Spot because a) he's more familiar and famous, b) he's way more popular and c) he's lots of times portrayed as a badass (even though he also lots of times is portrayed as a joke) which would make for a cool villain. They should improve on his character, but they should not try to make Shocker out to be something bigger than he is. That would take away part of why he's so popular: he's somewhat relatable and human compared to a lot of other villains. He's not in the same league as Doc Ock, and he knows it. Giving him the role of a leading villain would be untrue to the character we love.
I think why it's harder to justify spending time and energy on trying to make low tier villains better on film compared to other media like comics and cartoons is that there is such a limited time for films to do that. There are way more people who long for Kraven or Mysterio to show up that it would even feel a bit unfair.
If Marvel for some reason make The Spot a higher tier villain by writing great character evolving stories that come to define him more than his place as a joke villain, then after that he might deserve a place in the films.
