After playing Viego top for multiple games, here are my thoughts I know a lot of people, including myself, wanted Viego to be a viable toplaner. I've tested him for quite a lot of games and here are some points I found out:
- his early game is alright, but far from lane bullies,
- his 1v1 potential throughout the game is... Ok. I honestly expected more from an on-hit based skirmisher. He can't beat juggernauts nor duelists when on even gold.
- he excels in situations where he can cycle through multiple champs and ults so he is great in 2v2, 3v3 skirmishes, 
- is he viable top? Yes to some extent. Is top better than jg? No, he does quite a bit better jg.