So, recently games workshop posted a preview of new information from the upcoming T'au codex. This preview can be found
here. As a T'au player, especially one who loves the idea of a
ghost battlesuit team, this makes me very excited. I've been looking at putting together a T'au army optimized for stealth, hoping that early board control will make it easy to lock in a victory, since my local meta centers around very mobile armies that don't do so hot fighting from their deployment areas.
Considering the update, firstly, the Ghostkeel buff that gives enemy units a -2 to hit if the suit is accompanied by stealth drones and the enemy is 6+" away rather than 12+" is very, very nice. This means ghostkeels become untargetable by the bulk of Ork shooting that I've experienced, and makes it hard for most other things. This allows super easy harassment with an iron raker/fusion blaster setup. Secondly, the ability to set up a unit of stealthsuits, do their shooting, and retreat with no problem still able to shoot at the units I was harassing seems excellent. Pair this with Commander Shadowsun, and things get even easier.
Having looked at and considered all of this, I'm cogitating building for stealth control of the board, right from the get go. As of now (on the power rating system), the following is my list.
The railsides allow for artillery and anti-tank support from my backline, with my APCs moving into position (plugging any gaps in terrain that would allow easy access to the backline) and unloading their respective breacher teams. The strike teams move into formation around the railsides, preventing easy deepstrike access and serving as mostly a cushion, while the pathfinders use their vanguard ability to move into cover as quick as possible so they can serve as a markerlight platform for the railsides/warriors. Flamer suits and commanders (save for shadowsun) are in manta hold, waiting for the opportune time to land and go to work. Thus far, my strategy is the same as it always has been. However, the Ghostkeels, Stealth Suits, and Shadowsun are new additions (removing my two old riptides and some dudes). They all take advantage of the infiltrator rules, essentially deepstriking right from the get go already in cover. Then (codex willing) they can make use of jump-shoot-jump or
JSJ to deal with enemies as they try to push out of their deployment areas. I don't expect to hang on to any of these guys for long, so the wall of mirrors is used as a stratagem for gaining some additional shooting after the stealth suits inevitably get charged, with the Ghostkeels leveraging the -2 to hit protection and decent weaponry to deal with vehicles and other mid to heavy armor targets. Considering that Ghostkeels are tough enough to take a hit and look pretty big and mean, this is a pretty decent distraction tactic in my opinion (carnifex I think is the term?), but I haven't gotten the chance to try it out. All told, I should be able to execute the enemy army rather quickly. And, assuming we're playing for objective control, I can move my troops into controlling positions extremely fast.
I may have made some mistakes here, as this is my first truly formal list. If I have, feel free to notify me below.

Wall of words aside though,

if there are any T'au players out there with tips or recommendations, I'd love to hear them!