They just made Jungle Kog'maw more than viable. They made him strong.

His new W with a sated Devourer and BotRK is absolutely insane. I won't explain why (any Kog player should understand how brutal this combo is) and instead focus on his jungle clear.

With the -mr in jungle in the most recent patch, his W now hits significantly harder at level 1. Start nail. Nail and his W will provide roughly 40 bonus damage on hit and with attack speed from Q and some runes/masteries, you should be hitting twice a second on your first clear. This gives him a rather quick jungle clear.

I can clear every jungle camp without a leash and still have almost full health. The only oddities necessary for this are armor glyphs (the extra armor is really nice, as he has a hella fast clear but really low base armor) and savagery masteries (you should be getting anything that is on hit). You don't need armor glyphs but then beware of counter jungles. With the armor glyphs, I find his slow works great for getting away, or even destroying, counter jungles as it shines in tight areas. The only real counter jungle that I've struggled with had a jump (a Vi, specifically).

His ganks can be really strong if you have strong CC in lane as you'll do insane damage, shred armor/mr and his range means that you can surprise enemies easily and they cannot simply flash out of your damage range. Also, his range allows you to rush Devourer and BotRK before getting defense, making ganks stronger and clearing quicker. Without strong CC (like if you have Vlad on your team), you'll need to wander into lane and line up your slow appropriately. Champions with a jump will be impossible to gank if that lane doesn't have CC.

Late game, however? Kog will absolutely shine. Try this out and post comments. I'm predicting it now, this is a very viable jungle and you'll see it a lot more soon.