>>280772375The tragedy of Revo/Evo isn't that they tried to adapt S1, it's that the writers went back to trying to adapt the light novels instead of continuing to make their own story like they did with Try. Revo/Evo are poor interpretations of Vol. 4-6, which had been skipped in Slayers OG. The advantage the anime had is that the main cast had reasons to want to be off-Continent entirely.
Since magic is a lost art outside of the Barrier, Lina is the strongest person wandering outside the Continent with the exception of Knights.
Gourry lost his Sword in Try, and the anime hadn't broached the topic of the Blast Sword yet; it could very well have been outside of the Barrier the whole time.
Zelgadis still needs a cure for his chimerism. Since the Aqualord is dead, the Claire Bibles are gone, the golden dragons won't let him get access to their information, and he has no connections to Zephilia's Eternal Queen, he would want to look for a cure anywhere in the world.
Amelia, as the princess of Seiruun, would want to actually begin diplomatic dealings with foreign nations like what the Kingdom had tried at the start of... Try.
The writers of a theoretical fourth season were handed a blank slate, and they didn't trust in their abilities to make something as off-the-rails batshit insane as Try a second time. And I think that's very sad.