Once again, the amount of data I have here is a LOT so I won't be showing many pictures. You can again find the raw data on my spreadsheet. Quick reference for format: All the numbers are assuming a combat period of 10 minutes with scripted / "perfect" use of abilities and averaged proc chances. Green highlights are when each specific talent option (LB, BoB, no talent) will always be better, teal highlights show when another option is only temporarily better. Things to keep in mind are that this is not meant to be a measurement of specifically when SI becomes less valuable than other options, merely to find whether it does, the general ballpark, and trends across all brew gen talents. As well, the numbers shown are theorycrafted, which means you should take them with a grain of salt. Things won't line up perfectly like this in game. That is especially true of BoB and it's effectiveness, as right now its numbers assume you waste 10% of the energy regenerated and can use all charges. This is very optimistic.
To get right into it, I actually have a graph for you guys this time!
So to talk about this graph for a sec, this shows the rough number of charges gained as you get more haste, your tier 19 4-set, and ranks in Face Palm. Each high point in the slopes represents when you have three ranks in FP and your 4set, with the new low being when you increase your haste by 5 but drop those perks.
Now obviously, Black Ox Brew is killing it right now, as it should. It's an active ability which requires very good timing on the part of the player to maximize its effectiveness. Light Brewing, king before the nerf to the base brew cooldown, is still fairly solid and only becomes ever so more competitive the more haste we have. The last two are where it gets tricky for brew generation. Secret Ingredients is actually very marginally worthwhile compared to no talent at all, but only until you get both your 4-set and 3 ranks in Face Palm, where no talent ever so slightly takes the lead. Again I do want to stress that this is theorycrafted data, which does make specifics like that imperfect and not wholly absolute. Being said, the general patterns and trends should translate into the game. So let's dive into the data and see what's going on here.
For starters, the biggest thing to notice is that you're getting a decent chunk more Keg Smashes. The problem there is that they are at the cost of Tiger Palms. Because both share the resources of energy and GCD's, you only get so many and more of one comes at the cost of the other. What's happening though is that the extra Keg Smashes are pretty significant (about 50% more at base haste), these come at a very significant cost of Tiger Palms. And because there's less Tiger Palms, the talent is inherently throttling itself when the other options don't have such mechanics. Looking at the differences between the 30% proc rate (which is also on the sheet) and the 50% proc rate, we're seeing a good number more Keg Smashes with the new iteration but again, much fewer Tiger Palms.
Ultimately, the 20% increase on the proc rate only results in 1 or so more charges gained across a 10 minute fight with no interruptions and as perfect a cooldown usage as possible. More or less, in regards to brew charge generation, it's negligible. Being said, that's a lot more damage opportunity, but as shown in the graph, at a fairly steep cost to defensive power. At three ranks of Potent Kick (+1.5 seconds total on ISB uptime), if you want to just be able to maintain ISB fully (which I don't think Blizzard is intending), you need 80 brew charges. BoB can do this at 0 haste and no ranks in FP / 4-set. LB can begin to do this at 10% haste, 3 ranks of FP, and 4-set (though it dips down afterwards). SI can do it at 25% haste, 0 ranks in FP, and with the 4-set (again dipping down afterwards). Those are some pretty far apart numbers.
Realistically, the issues with SI at least from a defensive standpoint really stem from the opportunity cost that KS shares with TP, very specifically because in the current iteration of the spec, TP is very important to maintain because the brew charge artifact perk, and set bonus really only focus on buffing TP. As shown on the graph, these things make SI relatively less valuable compared to even baseline and really the talent just throttles itself because of said opportunity cost. The more KS' you use, the fewer TP's, which means fewer procs. It ultimately seems to balance out the brew generation regardless of proc rate.
But the ultimate question I think is whether or not Blizzard intends for this talent to be the way hardcore raiders can get back that desired trade-off of defense for damage. If it does, it seems like it's a good way to do it, though I think it could use buffs in other ways than proc rate, like perhaps reducing the energy cost of KS when procced. If not wholly intentional, then I think a rework is in order. This was on the wishlist of my friend LeBlue, but maybe have it so that you get a second charge of KS that only activates when SI procs so that you don't just have weird RNG with the cooldown resetting a couple seconds before it's up, which wastes it. This is an issue that I see becoming ever more prevalent the higher haste you get, which could explain why the ratio of KS' compared to other talent options is reduced the more haste you get on the table. This way, you can hold onto the second charge and use it while the original CD can tick away as normal. Perhaps a combination of both options would work.
Another big issue is actually the t19 4-set and to a lesser extent, the Face Palm artifact trait. The 4-set is a temporary issue but both exacerbate the problems that SI has. Another potential facet of the solution is to change how these work... give them the same effect of better brew charge generation, but in different places. Maybe on Keg Smash. Another possible avenue is changing either KS' or TP's energy cost so that they are the same baseline, rather than just on proc. Either way reduces the opportunity cost. I think the biggest thing with SI is that there's not really one thing that will likely significantly change it, if it needs changing at all in the eyes of the devs. Any meaningful changes to the power of this talent would need to be directed at manipulating or breaking the opportunity cost and negative feedback loop the talent maintains.
So right now I think the data supports discounting SI as a serious defensive talent option and pretty much relegates it to being used purely for damage if you are 100% confident in your survivability. Ultimately I don't know what the devs want from this talent, it's just my hope to give as much info to everyone in the community as possible. This might be intended, it might not. My job is mainly just to parse info, I can only speculate on design intentions. We can only just wait and see how Blizzard decides to go forward and while I understand sometimes that's a difficult thing to ask, it's the reality we have.
Thanks for reading guys, hope this has been enlightening. As usual, feel free to throw me a message on twitter if you're interested in chatting further!
~ The Brewing Scribe