right, this is IMHO the best way to play Tau, mecha Tau is vunerable to Anti Tank but semi-Tau gets around this by having the neccecary tanks but not too much.
a solid base to work around for 2000pts would be
Devilfish Squad 220pts
Devilfish Squad 220pts
FW squad 140pts
FW squad 140pts
Kroot 140pts
860pts
this allows for you to spend the rest of your points on tailoring the army to suit you, the FW and kroot provide a static firebase while the fish squads are the most versatile unit in the tau army, this imho opinion needs 2 HH to add more firepower to it and then sprinkle with a shas'o and some suits to season and you have an army