Three recent disappointments for me were Kyurem, Durant, and Heatmor.
Kyurem is good, but I was expecting him to be great. If his Glaciate move were 50% freeze and 100 power (An Ice version of Ho-Oh's Sacred Fire) that would have been very cool.
Durant seemed useable, but its speed could have been a bit higher as well as attack and it disappointed me the couple of times I used it in Showdown.
Heatmor was just pitiful. It seemed like a weaker Magmortar with the gimmicky eating moves you'd expect from an anteater (Bug Bite, Spit Up, Lick, Swallow).
Hey. I've been gone for awhile. Now I'm back (temporarily at least). Nobody gonna clap? Ok that's fine...