Because that's what the Star Forts were for. Had there been no cannons, there would have been no Star Forts, but now were just debating for the sake of debating. Like I said, I'm fine if you guys wanna make Taneth a Star Fort, I'm more than willing to make that concession if it makes you guys happy but it doesn't change the lack plausibility that Taneth would just so happen to have a defense design that proves wildly effective against cannons when there's been nothing to demand such a drastic change in the cities design. On the other hand, the time frame for advancements of cannons in our timeline fits that of Sentinels and their application in Sentinels navy coupled with the fact Sentinel was a naval power would push for better and more advanced design in my opinion.
It's hard to imagine that the idea didn't just come to mind because we decided to apply the cannons in the field. By now it feels like were just trying to make it so that the Yokudan's can't use the advantage given so that the Knights can have a 'fairer' chance at winning. I could definitely see new designs be created after the fall of Taneth at the hands of the Yokudan's cannon supplemented army, but given we've not used them in sieges before and the tight time period I don't see how Taneth having that sort of design just because.
But like I said, all that aside, its cool because cannons simply aren't the focal point of my strategy. Star design is fine, like IB said all we can do now is nit pick.
It sounds to me like you're saying "This is why this shouldn't be...x y z...but it's OKAY i guess..."
Well the truth is there are plenty of anachronistic things on both sides, Napoleonic artillery being one of them. Simply counting from the cannon's conception in Tamriel's war, several hundred years and just saying "ok by now they get these sort of cannons" isn't necessarily what would happen either. There's also the issue of the number of cannons. 450 cannons is the number a 19th century army would have when wars were fought with armies numbering in the hundreds of thousands. So i mean we can point things out too if it comes to that. There are plenty technological achronisms to go around that we ourselves have brought in let alone what TES military lore is in general.
Next, do you realize what 450 19th century cannons would do to a typical regular straight wall? I think having a unique design for Taneth in order to even make the siege balanced is kind of required. But maybe I could be wrong? If everyone wants regular ol cannon [censored] victim walls we can go with that too if it's everyone's meow.
Anyway it's nice people are still passioned by this plot and I hope we go through with it. Better to discuss ideas now than mid RP.