Here are my initial thoughts on the "new" Codex.
I'm a little disappointed with next to zero unit tweaks. We get Crisis teams up to 9 now which means crisis bombs no longer require Farsight. I do like the support turret that Firewarrior Stikers can now take. However, I don't like that Striker squads are 5-12 but the new Stiker/Breacher box only makes 10 models. And Riptides, HHs, and Skyrays in teams of 1-3 is nice. Oh and the fire team rule that gives units with the rule and at least 3 MCs or 3 vehicles increased BS. And CIB and AFP no longer signature opens up some interesting crisis builds.
As for new units I love the Ghostkeel and I am staying open minded on the Stormsurge. I really like the idea of Breachers in 'Fish for very aggressive play. Not a big fan of the Coldstar Commander but I do like the new Crisis and Commander boxes with more pose options.
And now for the really great part: Tau Decurion and Formations!
First our Core formation, Hunter Cadre. I really like this setup as there really isn't any tax to it as it is basically just a CAD Force Org that adds an extra mandatory Elite, Troop, FA, and Heavy so it really isn't much different from lists we already have. For that almost CAD list we gain Supporting fire at double the distance between units and a bubble around the cabre's commander and fire blade that lets us run or flat out and then shoot. This is especially nice for the fireblade as volley fire only mentions remaining stationary in the movement phase letting us have some mobility with strikers pairs with fireblade and still get the extra pulse shots.
This leads us nicely into our Decurion, the Hunter Contingent. We have to take at least one Hunter Cadre and have the option of taking up to 1 Command formation (the only spot to include an ethereal in the Contingent), and have to take 1+ auxiliary formations (more on these later). For the Contingent we lose ObjSec and gain Coordinated firepower. Tau can now properly MSU! Getting to combine the shooting of any number of units and resolving their fire as a single unit (which includes marker light usage) means we no longer need large squads to achieve ML efficiency and gives us very good tools to use against deathstars and other big nasties. Now, hopefully this rule gets FAQd because there is already a great amount of debate as to whether the resolving the combined shooting attack "as if" a single unit means the participating units share USRs and if Target Locks also work and let such equipped units fire at different targets from the combined "metaunit". Obviously, shared USRs is huge as a buffmander with command and control, multi spectrum, and puretide engram spreading twinlinked, ignore cover, and tank/monster hunter to everything is amazing. Personally, I am of the belief that USR do spread and Target Locks do work. It's really no different from our old codex's with vehicle multitrackers letting our tanks fire "as though it were a fast vehicle". Since they resolve their shooting as a single unit then they follow all other rules for a unit at that time. But further discussion of this can move to the Rules board until there is a FAQ.
For our formations we get:
Retaliation cadre: another commander, some more crisis units, broadsides, and riptides. The entire formation gets relentless (yay mobile broadsides!) and the entire formations can arrive via deepstrike on turn two and get improved BS on the turn it does so. Pair this with units with homing beacons and this becomes a accurate deadly assault.
Heavy retribution cadre: a unit of ghostkeels and a pair of stormsurge units. Giving stormsurges essentially twinlinked as long as the ghostkeels are close to the target is very powerful for units that put out as much firepower as Stormsurges do. They also limit target movement and charge range if two or more of the formations units fire at the same target. The only downside is point cost (not to mention money). You're looking at a bare minimum 850 points to field the formation.
Infiltration cadre: 3 pathfinders, 2 stealth, and a piranha unit. If any unit in the formation is destroyed ALL of the rest of your reserves come on at the start of your next turn. And each unit that gets 3 or more marker hits gets a free seeker hit on that target.
Optimized stealth cadre: 2 stealth and 1 ghostkeel unit. when shooting, you can have the ghostkeels and any stealths close enough use wall of mirrors. They get ignore cover, +1 BS, and hit any vehicles on rear armor! Note, if part of a contingent and you have them combine fire they also get the BS bonus from coordinated firepower as well!
Firebase Support Cadre: 2 broadside and 1 riptide unit. They can choose to shoot as a single unit (note - different from contingent rule) and gain tank and monster hunter.
Armoured interdiction cadre: 3 HH and 1 Skyray units. Note, this is the only way to take a skyray in a hunter contingent. In your shooting phase, you pick a point and the formation re-rolls misses against targets close to that point.
Air Caste Support cadre: 1 Sun shark and 2 Razorsharks. They can regain lost hull points on a roll and can ignore penetrating results of shaken or stunned on a roll.
Allied advance cadre: 4 kroot and 2 vespid units. The vespids gain infiltrate and stealth. The kroot carnivores close to the vespids get shrouded instead of stealth and increased BS. They also gain supporting fire but only with units in the formation.
Drone Network: a unit of drones. no special rules
Command (Contingent Headquarters): 1 Commander, up to 1 ethereal, and 1 or 2 bodyguard units. no special rules.
Personally, I really like the Hunter Contingent. The detachment doesn't really have a tax as it really isn't much different from a regular Force Org. I like the idea of taking a single Hunter Cadre and an Optimised Stealth Cadre. Maybe add a retaliation cadre for larger games. Sadly, you have to use a Contingent Headquarters to include an ethereal and darkstrider and farsight cannot be including in a hunter contingent at all. I'm toying around with including a CAD with ethereal, darkstrider, and 2 squads of kroot and joining darkstrider and the ethereal to squads of breachers for some very aggressive mobile firepower. There are so many good synergies here. Even just with a single breacher squad in a devilfish. Move the fish, disembark the breachers and the drones, then have all 3 combine fire for increased BS all form a single breacher squad and it's transport. That's just a simple example of what can be done with the contingent.
What do others think of the codex so far?