I do think Warleaders are good for solo play but as others have said here its not often that a Freep will stick around when things are not going their way and they all have at least one flight skill or simply call in reinforcements before you kill them. I still love my WL though.
I made a Reaver recently and got him to rank 8 and he can take on any class. I really have fun with my Reaver. Shield Wardens and WL spamming LMs are tough ..but then they are for any Creep class atm.
Rank 12 Warleader, Flaprat Rank 11 Reaver, various other ones i'm useless at...