not really, but I will if Raikou comes back. I missed out on Raikou (the only one I missed) - I just happened to not be caring about the game anymore for that period. So when it came time to get ready for Kyogore I had to power up my Zapdoses which weren't even that great.
I more regret having some awesome Gyaradoses that I barely take for a spin anymore after Kyogore. I sunk a lot into those guys.