Hoechlin is more convincing than Tom Welling ? Wow. Granted Welling never actually played Superman but for me at least, he was as perfect as I've ever seen as CK. If I had to design a Superman from the ground up I think he'd come out looking like Tom Welling.
I find that astonishing. I think Welling was badly miscast. There were moments in later seasons where, if I was in a generous mood, I could almost see him as a marginally plausible proto-Superman, but most of the time I was very unimpressed.
I think part of the issue is that you seem to be going almost exclusively by appearance, whereas to me, the vocal performance is also very important. Welling's constant dull mumbling got on my nerves. There were occasions when he gave a more convincing performance, so maybe the writing and directing was more at fault, but I just never liked him much. He's by far my least favorite live-action Clark Kent.
Dean Cain played Superman and CK far differently
I'd say "slightly differently." There was virtually no difference in his vocal performance, and Cain has a rather distinctive voice and a rather Shatnerian, pause-filled rhythm, so I never found it credible that people couldn't easily recognize that Clark and Superman had the same voice. I'll grant that his Superman was a bit more formal and authoritative than his Clark, not as laid-back, but the voice was so much the same that it outweighed that for me. I never found Cain as convincing as Superman as he was as Clark -- which isn't surprising, since the first-season producers wanted to minimize Superman's presence and so they cast him to be Clark first and foremost. (Which is probably why they picked Cain over his runner-up, Kevin Sorbo. I think Sorbo would've made a much more convincing Superman, though I don't know how effective his Clark would've been.)
James Olsen ? Better tell Superman that, he called him Jimmy in the show.
As James said in the pilot, that nickname was reserved for his mother and "the big guy." Olsen wanted to get out from his "boy sidekick" image and establish himself as his own man, so he moved to National City and started going by James, but he still let his mother and Superman call him Jimmy because of their long-standing relationships. That's hardly implausible.
Besides the point anyway, this isn't about his character development, which I actually find very refreshing, it's about the fact he is more physically imposing than Superman. To me, that doesn't sit quite right.
But as I tried to explain, it fits well with the intent behind this version of the character, which is that he's
not the boy sidekick anymore, that a decade has passed and he's outgrown everyone's image of who Superman's Pal Jimmy Olsen should be and is trying to make a name for himself beyond that preconception. So having him now be taller than Superman illustrates that "outgrowing" very nicely. He's not
supposed to be the same as the Jimmy we're used to. That's the entire point.
we were promised the Superman we had been waiting on, I think Superman works best as a clean cut kinda guy. I know this show has mastered the art of re-imagining characters, and on the whole I'm fine with that. Superman in my head canon though is untouchable. I don't wanna see him appear scruffy and unshaven. It doesn't work for me
Well, I'm not sure that's even fair. Some men -- myself included, to an extent -- just naturally have pale skin and very dark hair so that, no matter how clean-shaven they are, they still have a bit of shadow visible on the chin. And modern HD cameras would show that more clearly, so it'd be harder to hide. So frankly I think you're being pretty damn insulting by assuming that any man with even a trace of stubble visible must be slovenly and unwashed. I mean, what, are you posting from 1954? Standards have changed. These days, a bit of stubble is considered perfectly acceptable for a well-groomed man, even desirable and fashionable.