As soon as I saw that they were reworking Galio i told myself "man i hope i can jungle with him"
And then when they released his abilities again I thought "oh man I think im gonna be able to jungle this dude"
Then today he got released and I got to jungle with him... went 7-6-17.
I had a malph on my team that gave me incredible follow up with my ult, was able to turn around 2-3 fights that should have been loses without it. He plays kinda like a Shyvana imo ( as in you just kinda farm until you are you strong, gank if something is open and easy)
The clear was eh, comparable to a zac clear, but with less sustain since you really only have 2 moves to clear camps with. Ganks are awesome with your ult, but even without it if you can position right your golden.
All-in-all I would say yes he can jungle, but it heavily depends on your team comp, and if your team can survive without you for a bit while you get your cinderhulk.