I couldn’t tell you precisely when Koei started making “good” musou games (a ways into the PS360 gen, I want to say) or exactly how many they released prior to that point but I feel like it took at least a dozen tries, including expacks and so on.
I’d hesitate to describe either of the recent Bubsy games as good, for the simple fact that they’re obviously degraded, low-budget rehashes of existing indie games (the Great Giana Sisters reboot and Bit.Trip Runner 3, respectively) that exist solely to capitalize off people who’ve been making the same one Bubsy joke for thirty years, and are so slapdash that they make you question whether the originals had any redeeming qualities to begin with (not that either of those games were amazing pre-Bubsy, mind).
If CV didn’t get good until Symphony then we all have no choice to accept that Valis always sucked.