The Krootox are a TERRIBLE buy; I'd never seriously consider them. I had some free points in Army Builder and tossed 'em in for fun. Heck, I don't even like Kroot that much.
The problem with seriously running the numbers is that JTS1486 is always right in the end (dammit). It's hard to justify adding 50 points to a Firewarrior squad especially since many of their shots would be wasted. I actually couldn't find a good place anywhere in the list for the markerlight drones; they're too expensive. What this means is, "Does anyone want to buy a pair of markerlight drones?"
I really wanted a Tau army with a fair amount of Firewarriors (I'm a big believer in troops) and lots of markerlights, not just markerlights from one squad of Pathfinders. I think that the Sniper Squads are the best way to do this, especially because you can split fire amongst different targets as needed, they have a BS4, and the stealth field keeps them safe from most shooting.
Here's my revised army:
HQ +Shas'
el w/ Cyclic Ion Blaster, Burst Cannon, Targeting Array,
HW Multi-Tracker - 88
(this guy is designed to pump out 8 anti-infantry shots per round, and hit with 6+
pf them)
Elite
+Crisis (x2) w/ Fusion Blaster, Plasma Rifle and Multi-Tracker - 124
(these guys are spot cleanup for trouble targets, especially indirect artillery; they can deepstrike when allowed, assisted by the Pathfinder's Devilfish on occasion)
+Crisis (x3) w/ Plasma Rifle, Missile Pod and Multi-Tracker - 186
(classic Fireknives, the squad is three strong to get the most benefit out of markerlights)
Troops
+Firewarriors (x11) w/ Pulse Rifle + Shas'ui w/ Pulse Rifle - 130
+Firewarriors (x11) w/ Pulse Rifle + Shas'ui w/ Pulse Rifle - 130
(The Shas'ui is there for the leadership boost)
+Firewarriors (x12) w/ Pulse Rifle + Devilfish w/ Targetting Array, Multi-Tracker and 2 Seeker missiles - 235
(for mobility and objective grabbing)
Fast Attack
+Piranha w/ 2 Seeker missiles - 80
(for harrasment, assault redirection)
+Pathfinders (x7) + Shas'ui w/
HW Drone Controller + Shield Drones (x2) + Devilfish w/ 2 Seeker missiles - 236
(For the bulk of the markerlights; they will be attracting a lot of fire, hence the shield drones)
Heavy Support
+Broadsides (x2) w/ ASS + Broadside Team Leader w/
HW Drone Controller + Shield Drones (x2) - 275
+Broadsides (x2) w/ ASS + Broadside Team Leader w/
HW Drone Controller + Shield Drones (x2) - 275
(The meat of the heavy weaponry in this army; moderately mobile and a bit durable)
+ Sniper Drone Teams (x3) - 240
(For markerlight support plus fire-splitting sniper drones)
This army list is more efficient if a bit more vulnerable to assault. The drones from the vehicles will be detached and sit in front of some of the static squads to help soak charges.
-=Edit=- Heh, I'd already done that math by the time you posted that last bit, JTS1486. You had me at Hello!