Eh. We'll venture into this with reservations. I expect Rummy will be slapping us with a vodka-covered lock here pretty quick for wishlisting. Oh well, it can still be fun.
Ethereals:
Mostly useless, only provide a Ld bonus and are more useful dead for the benefit this provides.
BS 4 honour guard are a useful extra unit of Firewarriors but provide minimal protection to their Aun.
Ethereals really need re-adressing.
Ethereals need to be fixed. I'm hoping in the same vein that Necrons will have "psychic abilities" that are really technological, that Ethereals will have the same type of abilities. If our powers were anything like the GK rumors, this should make ethereal's easily worth it again. Assuming they actually get some decent armor this go round.
Kroot:
In their current incarnation Kroot Carnivores are typically used as shock troops and cannon fodder or as a distraction element. In 5th edition I would expect to see Fieldcraft replaced by more useful universal special rules such as Stealth and Move Through Cover. This means that Kroot would recieve a cover save regardless of the terrain they are in which would mitigate their low armour save.
This is really just a 5th edition update. Kroot aren't bad for their price, except for the Shaper. The fact that he has three wounds is stupid, as well as the fact that he is three times more expensive. He needs to be cheaper, realistically 1w, and have some wargear options, as well as possible evolutionary mutations.
Vespids:
Stingwings are drastically in need of revision. In their current incarnation Vespids have the Fleet rule which classes them as assault troops - a role for which they are ill-equipped. In some ways Stingwings are similar to Dark Eldar Scouges but in most cases the Scourges will run rings around them.
Vespids don't fill their roll properly. They're supposed to be hit and run harassing units with a decent gun. They currently are a weird blend between a combat unit and mid range harasser, and don't do either particularly well, especially for their points. They need to be put in one catagory or another. Preferably the harassing one, since this is Tau.
Gun Drones:
Gun Drone Squadrons are in many ways useless and in my experience rarely used. I think they are a waste of space on the list and I would love to see them scrapped.
Why on earth would you scrap a unit? Gun drones have a lot of potential. Make them troop choices, or FOC-less. That immediately brings up their worth significantly. If they're FOC-less, make them be 1:1 with the amount of your firewarrior squads. Give possible upgrades to heavy gun drones, and what you have is a jet pack (troop?) unit that can carry heavy weapons, and is cheaper than firewarriors in a fish.
Piranhas:
I think the codex Piranha should be replaced by Forge World's superior TX-42 Piranha. The TX-42 features better front/side armour and it's twin-linked weapons are more acurate and more useful than gun drones. Sadly though, I somehow doubt that GW will bother. If you ever play against me though - expect a squadron or two of TX-42's, they're awesome!
I think it should be a codex-approved upgrade option, similar to Landspeeders versus Landspeeder Typhoons. Additionally, giving them other weapon options besides gun drones would vastly increase their worth. Crisis suit weapons could be thrown on here, so we have more than two possible units carrying plasma weapons.
Rail Rifles:
The rail rifle is simply a long range pinning weapon useful against power armoured opponents. This is a far cry from the sniper rifle it is intended to be. The most obvious improvement to this weapon would be the inclusion of the Sniper rule which would allow it to pick off specific targets.
What? No. The rail rifle is superior to a sniper rifle in almost every way. That's also not what the sniper rule does, you might want to check your BRB. The Vindicare assassin can do that, but it's his special ability, not the sniper rule.
The rail rifle is perfectly fine the way it is, it just needs to be distributed to more units. A rail rifle\missile pod combo crisis suit sounds great to me.
Sky Rays:
The major down-side of these gunships are their limited supply of seeker missiles and their short range (36") in the absence of infantry markerlight hits. This means that to fire it's own missiles the Sky Ray's range is a pitiful 36" which is too close for a Tau gunship. This also means that the Sky Ray is only ever a support element with a limited supply of seeker missiles.
To amend this problem for 5th ed. I would prefer to see the Sky Ray's seeker missile quantity increased to an unlimited supply but it can only fire 4 per turn. I would also recommend increasing the range of the gunship's markerlights to a respectable 48".
Well, okay. 36" isn't exactly pitiful, after moving 12" with a markerlight, you can reach out and touch a majority of the board. Nevertheless, it's 6 seekers is a horrible gimp that needs to be addressed.
Overall, we're going to say the same things we always have. Markerlights need to be reworked, Devilfish need to be cheaper, Firewarriors need something, ect. If we were going to go back through this, I want people on this board to consider the recent GK rumors as well as the rest of the recent codices, and notice that the power level
is being upped. Tau will need to do that just to keep pace. Yes, you guys and your great strategies and one-list-armies think Tau can still compete, but the codex is showing it's age and needs to be brought back in line so that a novice with another codex doesn't give a Tau veteran a run for his money.