When I said CW, I also meant to include the previous network, The WB. There was a clear focus with this series on the network. The relationship aspects, Clark's love life, are the central focus. On the WB, there was teenage angst and a 'Dawsons Creek' take on the material.
I'd partially disagree with you, while I agree there was to a certain degree a
'Dawsons Creek' like approach to certain aspects of the material, ultimately it played out pretty much like what you'd expect an origin story revolving around a young Clark Kent. It focused on him struggling with coming to terms of who & what he is.. in early seasons I mean.
This season, it's more than obvious they're pandering to shippers (as they have been for years), that's why this 'Clois' stuff always gets such a huge central focus. Prior to that it was his drama with Lana.
It isn't so much pandering to shippers its more a case of the story needs a love interest & because of the circumstances of the way the show has been done it would be almost impossible to not have them in some form of relationship prior to his glasses & whatnot.
To the point where it stopped becoming a Superman early days story YEARS ago, and more of a DC showcase. To the point where cannon was drastically altered to keep the show afloat and gimmicks introduced; Lois brought in early, their relationship before Superman, living together, engagement,... Supergirl's introduction, etc Essentially they've shoe-horned pretty much everything from Superman's future career, into young Clark's Smallville present....regardless of whether it fits or not, and the overall picture is very convoluted.
In my opinion alot of the introduction of other characters/elements from Superman's future as you put it, fit & have been largely acceptable in my view. With a few alterations I'd take some of them as cannon as well. Particularly alot of the Kryptonian related elements they've introduced like Zod, Doomsday & Brainiac in particular. Doomsday was made to work because of how they'd seemingly given him/it abit of an origin with the Davis Bloom stuff. Dispite the anti-climax, non-fight, the actual arc itself was a good take & it ended very well & fairly in cannon what with it being buried underground.
One of the things that not so much annoys me, but gets me thinking about other Superman origins is how come Clark/Kal-El is able to grow into a fully grown man before all these super-villians & problems start really coming out of the works
(& as I said, particularly the majority of Krypyonian ones).
To the point where Clark is in his mid twenties and still can't fly 'no flights no tights' when everyone else can, and when even a third generation hero like Stargirl is a fully formed superhero...
Don't get bogged down in him not being able to fly, in Smallville's story they've I believe given their excuse as to why hes been unable to fly as of yet, in the sense that like most of his other powers, its in his head. Nevermind that all the others have been able to fly, it's meaningless to Clark's reasons for not flying.
Also how's Stargirl a fully formed superhero? Because shes wearing an outfit more traditional to her character?

With all due respect to the Stargirl character, the Superman character is more complex, and in Smallville's Universe that complexity is 2x the usual.
Jeff East's young couldn't fly, he left Smallville at what.. 18? Then he goes to the FOS & leaves as Christopher Reeve's Superman when hes about 28/29.. this incarnation of the character might not have flown till he was 27.
Honestly, no. If anything the restrictions only helped Smallville. Think about it... what were the restrictions?
No Lois Lane relationship with Clark? Yeah that would have actually been a good thing, considering it doesn't make much sense in the context of his younger days in Smallville.
No Jimmy Olsen? Yeah. Jimmy is supposed to be way too young to appear during Clark's early days.
I consider both of these pretty irrelevant, Lois & Clark didn't need to be any any form of romantic relationship in his Smallville days, but her introduction as someone who briefly met/knew Clark as a teenager would have been a nice addition... however they kept Lois around for too long & as a result the cannon had to change to adapt to the fact she'd been around Clark for too long to not, not know he is Superman. They should have brought her in for a handful of episodes, sent her away & only brought her back after Clark had adapted some form of glasses or alter ego.
Jimmy Olsen never needed to be mentioned on the show, this character I mainly blame on the writers. They knew, that they couldn't have the Jimmy Olsen they introduced as the real Jimmy Olsen due to WB's restrictions... they wrote themselves into a hole & made a mess writing him out.
Crystal fortress? It was an aesthetic and didn't make a difference one way or the other.
Just an aesthetic..
Had they been allowed to use the Fortress in early seasons we wouldn't have heard Jor-El talking from a ship, then moving house to the Kawachi Caves then finally to the Fortress.
Also it wasn't limited to just simply the fortress, they could barely even mention Krypton & anything Krypton related in early seasons nevermind actually showing it due to the fact that Superman Returns was very Krypton heavy before the cut, I'd have much rather watched Clark learn about/see Krypton, Jor-El, Lara etc in the Fortress than watch him trying to fight a freak of the week that touches people to steal their body heat!
In my opinion cannon doesn't technically exist, it's all about preference. With that in mind in my cannon, the fortress is a key element to Superman's origin... doesn't have to be like an ice palace, I'd just rather it wasn't some Indian cave..
Inability to show the \S/ symbol during the first four seasons? Didn't make a difference. Unless he was in Superboy gear, he wouldn't need to sport the \S/ in highschool anyway.
Might not seem like much but it kinda messed with the shows continuity & flow, in the few things they could show they used the Kryptonian S which was more like an 8. Fair enough, but then when the
'ban' was lifted they threw in the normal logo in it's place with no sort of explanation on how/what or where it came from. This is more an aesthetic thing than the fortress, but if your doing a Superman origin, you kinda want to be able to have everything in place so you can explain who or what everything is correctly..
No Batman or Wonderwoman? Probably for the best after they butchered Green Arrow.
No Batman or Wonder Woman, fair enough not really relivent to me particularly. Would have been nice to see Clark meet or cross paths with a young Bruce Wayne.
How have they butchered Green Arrow?
The restrictions barely made a difference. TPTB are really to blame for everything gone awry with Stallvillle.
Disagree in the highest possible way in regards to the restrictions barely making a difference.
You can't make a show about the origins of Superman when you can barely mention Krypton.
In my view the 2 single biggest problems for Smallville have been the restrictions around the show & cost/finances.. then a **** network & poor writing/planning.