Of course, after I post this, I get a bunch of ideas.
First, currently I don't have access to my laptop, so I can't implement changes directly, but I'll post my ideas here.
First, Crisis Suits. Part of the design has always been to let them mix and match. As you've read in the Redux, I've taken away part of that. I've also expanded what the weapons can do, in the manner of Sternguard. I feel that this needs to go further. Crisis Suits, at least in my mind, are general engagement battlesuits that have a general purpose loadout that can take on a variety of things. So I propose that a Crisis Suit has a static choice of weapons, with the current options remaining:
Crisis Suit
Wargear:
Coilgun
(36", Str 8, AP 1, Heavy 1)
(24", Str 6, AP 2, Assault 2)
(18", Str 4, AP 4, Assault 4)
(36", Str 9, AP 1, Heavy 1) vre+
Suppression Launcher
(36", Str 7, AP 4, Assault 2)
(24", Str 5, AP 5, Heavy 4, Smart)
(18", Str 4, AP 5, Assault 1, 3" blast)
(18", Str 5, AP 4, Assault 1, 5" blast) vre+
These two weapons cover all bases that Crisis suits need to cover, giving a large variety of options. No more specialization can really occur. This is purposeful. I left it to the Hazards, whose weapons I envision as such:
Phased Ion Gun
(18", Str 5, AP 4, Assault 4, Rending)
The basic weapon, which can be upgraded to one of the following:
Fusion Cascade
(12", Str 8, AP 1, Assault 2)
Pulse Submunition Rifle
(18", Str 5, AP 4, Assault 1, 5" blast, Frag)
Flechette Cannon
(temp, Str 2, AP -, Assault 1, Rending, Poisoned (3+)
Yes, these weapons are MEAN. That's the idea. Hazards should be the suit that everybody fears. Tough to kill, but with the meanest scariest close range weapons that Tau have. If you are a unit the team has been designed to kill, you will DIE. That's the idea.
I haven't posted costs, but rest assured a full hazard team with drones would be ~400-450 points.
Stealth suits also need to be redone, my idea as such:
Weapon:
Burst Cannon (as current Tau codex)
Special Rules:
Disruptive Firing (as in current Redux)
Silenced Shooting: All successful cover saves against a Stealth Team must be rerolled.
I feel that this gives the Tau a much more interesting unit that what currently exists. Some of the other options remain, but certain pieces of wargear (the altitude thrusters, fusion retroburners and shimmers) are most likely to go. Asymmetric warfare can't be accurately represented by 40k, so I try and build it in.
Sniper Drone Teams also get the Silenced Shooting ability. Then I'd take them

Pathfinders:
Only a Veteran team allows outflanking. Only one PF team per Fire Warrior Team.
Markerlights: Big changes. Now, if the unit was stationary, mark a unit within 36". Different things happen for different units.
Markerlights in squads: If there is only one markerlight in the unit, the unit fires at +1 BS. If there were 2+, 6 seeker missiles may be fired at the unit. You may choose not to fire a markerlight, if you so wish (to use the BS increase and not launch seekers, basically).
Pathfinder and Tetra Markerlights: When one of these units marks a unit, all subsequent firing at that unit is twin-linked (or at +1 BS if the weapons are already linked), and all successful cover saves must be rerolled (or cover is ignored if enemy passed saves were already rerolled). These DO stack with each other and other army effects.
The idea is that Tau should have a few select weapons capable of ignoring cover, but Pathfinders make whole swaths of the army semi-ignore against a single unit. I haven't tried it out, but I think it could work.
Tetras and Skyrays: Need a slight reworking. I'll get back to you all on that.
Tau Special Rules: The Doctrines are gone. Special rules for individual units take their place. The Doctrines seemed added on at the end, instead of well integrated (which they were) so I'm glad to be rid of them.
A new special rule is to be added:
Tau Jetpacks: Tau may take their jetpack move in the assault phase after deep striking.
This I feel represents the Tau warfare well. Go in, kill something, get out. And if other armies can assault after DS, we can run away as well.
Thoughts? Gripes? Flames?
Cheers!