1) Like Regigigas (Slow Start) in NU. The Pokemon may be good but can also be decimated at some point by his Ability (Ex: Archeops with Defeatist in RU).
2) Can you bold all the Pokemon mentioned in 1) that can learn Pursuit?
The only ones I can think of are slakoth who has traunt and archen who has defeatist. And slakoth learns pursuit.
Source: personal knowledge and http://www.smogon.com/bw/pokemon/