Is a 100% Slowbro still a worthy gym defender?

Lost 7 attack and 4 defence, may as well use a Metapod instead. /s

It still holds its own. Just not as impressive cp wise

It really depends on your area. Is 2216 good enough to do well in Gym's or will it be at the bottom every time.

Well yo have 2 choices basically. You can put a Rhydon/Gyardos up in a gym and have it taken down easily by low levels and have to go back to the gym and train it again or you can potentially be at the bottom of a gym thats harder to beat but possibly you would be kicked out first or early. This is pretty much gonna be the gym dynamic for more common pokemon like Slowbrow.
Id try to strategically chose between these two options by gauging which would result in the best daily collection and least amount of gym maintenance.

Still pretty good, the nerf was mercyful with this one.