Tsareena actually has a good niche in UU in a utility role: http://www.smogon.com/forums/threads/sm-uu-beta-slowbronite-diggersby-tornadus-t-volcarona-scolipede-banned-post-165.3591786/page-4#post-7179506
Dhelmise and Decuidueye aren't good, though, you're correct about that.