Anyone who's saying crit Shaco is good obviously don't play Shaco.
https://www.youtube.com/watch?v=K9pFySZx2fs
Anyway, definitely go for Ignite/Smite on jungle Shaco; it aids your burst significantly at all stages of the game. As mentioned previously, animation cancelling is a big deal with Shaco, as it lets you Qaa > Hydra > E > aa > ignite as fast as possible. As far as damage goes, if you've been farming well and ganking a lot early, your mid-game burst should take at least 80% of a unit's HP, sometimes even 100% if it's a squishy who is underfed. Be sure to take Thunderlords on Shaco; the other masteries are situationally useful, but only Thunderlords actually increases your burst potential. Also, never use your box during an assassination attempt. It delays your damage by quite a bit due to its cast/arm time.
After the item cost changes I always finish my Warrior enchantment before anything else. The stats it grants in relation to its cost makes it extremely efficient, and Hydra is too expensive to be considered for a first item these days. Not only that, but Tiamat no longer passively cleaves, meaning it won't increase your clear speed significantly. I usually go Shiv as a second item for the burst and AOE damage. My third item is usually a Titanic Hydra, but you could also go Ravenous if it suits you; I simply prefer to build bruiser Shaco over the full AD variant. With those 3 items intact, your damage should be more than sufficient.