Why should Karth only be played bot lane? You said yourself he isn't bad top. Karth actually has a fairly significant contribution to the team-by leveling his wall intermittently at levels 3, 4, 10, and the last two between 12 and 18, he can actually use it as a good support move. His kit synergizes excellently with Hextech Sweeper, and Rylai's as well. He can still defend towers like a boss, and by getting Chalice/Tear+Sweeper over RoA, you gain a good deal of utility early without sacrificing build time.
While my elo is fairly underwhelming, I do have to question why Karth is placed in the same tier for top lane as...Udyr.
Also, can you please explain the bugs on his abilities? I have not noticed them.
Anyways, thank you for making this list . Mordor can't be ALL that bad if you have things like this there.