Breaking down Cinderhulk vs. Warrior
There was an interesting stat on Primetime League tonight (3/25/2015). The most played jungler in last week's LCS was Rek'Sai...and her W-L was 1-8. Now, this is only 9 games so I don't want to read too much into it, but certainly Cinderhulk has been a massive buff to tank junglers, and that 5 AD reduction to Warrior certainly isn't helping the Rek'Sais of the world (180 gold value reduction). I'm not here to comment on whether this is a change for the better or for the worse, but I do want to throw out some numbers so that junglers can think about what this means for the game.
Warrior enchant gives 40 AD, 10% CDR, and 10 APen (armor penetration), for a total gold value of 1877. If we view the upgraded Machete as sunk cost and just look at the enchantment (1400g), that's a very good gold efficiency of ~134%. (Of course, it's not very good if you consider the upgraded Machete, which gives no stats.) Cinderhulk gives 350 health, plus 25% bonus health (so, 427.5 health on its own). It's actually gold inefficient on its own, if we ignore the passive (costs 1350g and gives 1167g of stats). For what it's worth, I think the passive is probably worth that extra 183g, but that's just my opinion.
Now let's look at how Cinderhulk would fair in some typical builds. Only items that give health matter here, so let's imagine our bruiser jungler will be getting health from The Black Cleaver (+200), Locket of the Iron Solari (+400), and Randuin's Omen (+500). For a tank jungler, we'll replace The Black Cleaver with Warmog's Armor (+800). At full build, Cinderhulk will be worth 1904g for the bruiser and 2172g for the tank jungler, not considering the passive (or the Smite abilities from the upgraded Machete). For what it's worth, the break-even point for Cinderhulk to be worth as much as Warrior (without considering the passive) is 1060 bonus health.
What does all this mean? Once you've completed two major health-granting items, the gold value of Cinderhulk will be very close to that of Warrior; considering the passive, it's likely to be slightly better at this point, in general. At three other health items (or two with one being Warmog's), it's significantly better. Let's say you're playing Jarvan IV and building Ravenous Hydra/Black Cleaver/Locket/Randuin's/Merc Treads. Unless you really want the CDR, Cinderhulk is very likely better at full build than Warrior. So, if you build Warrior, you're looking to take advantage of a window earlier in the game when you have 1-4 items and it gives you a bigger power spike.
This leads me to the following practical advice: If you're playing a bruiser jungler and building ~1000 bonus health, you may want to consider trading Warrior for Cinderhulk once you get to full build; it's just a better item at that point. The main option this is competing with is building a non-Machete 6th item (like a Last Whisper/Guardian Angel/whatever), which may be a better value but does lose your upgraded Smite and also costs more gold to pull off. For a tank jungler, Cinderhulk is fully competitive with other legendary items in terms of gold value and is probably worth keeping.
Tacked-on balance rant (because this is boards): The enchant most similar to Warrior is Magus. Magus gives 80 AP and 20% CDR for a gold value of 2373g. That's about 500g higher than Warrior enchant (for the same cost). I think the 5 AD nerf to Warrior enchant was completely unnecessary. The problem wasn't that bruiser junglers as a class were overpowered; it was that other options weren't being sufficiently well-supported, and the Rek'Sai/Jarvan/Vi's of the world were probably slightly overpowered early in season 5. (Note: slightly.) Given that those individual cases received targeted nerfs, I don't understand why the Warrior enchant itself needed a nerf. Why, Rito, why is this enchant so much worse than Magus? Rant ended.
build it so they can help make plays and help snowball their laners. You'll see most of these champions go for defensive items after they finish their Warrior enchant as their damage potential falls off as the game progresses. Now Warrior enchant is very strong in the early game as flat penetration is incredibly powerful at early levels when champions don't have a lot of armor but is less useful later in the game when many champions have over 100 armor (honestly the gold value of flat penetration is skewed because of this). The addition of 40-45 AD and 10% CDR is great for an item that costs 2200 gold. The build path is smooth as well, building out of Brutalizer, which is a strong early game item to get after your second back.
). If the Warrior building junglers don't snowball a lane or themselves, they will become weaker than the tank junglers in the late game. If they are successful, there won't be much of a late game for the tank.