The tau fleet is very much a phalanx, designed to hold a shield wall and stab at the enemy with medium range fire and long range torpedo's. It's not really surprising that you got in the first punch. If i were the space marine player, i would not have done what he did
The strike cruiser variants are -indeed- powerful. I use them extensively in my grey knights fleet. I once had a single strike cruiser board it's way through two full health chaos cruisers one game, and a tombship the next.
Here is my overview of the tau options.
Explorer: still a viable choice, mostly because it's cheap. 230 points for 8 manta's is awesome, if you spend the extra points for torpedo bombers, it gets crazy.
hero: I still can't get my brain wrapped around this ship. It must be the look, which i just can't come to terms with.. I like the protector so much more. Still, four ion cannons and 8 hits is just hot.
Merchant: this can be a mean little gunship, but mostly it's for taking grav-hooks on the cheap.
All old tau escorts but the Nicassar dhow are outdated, and simply should not be used.
Custodian: A proper carrier battleship, and with the special commander, it turns this thing into a nightmare for enemy ships. great firepower, great ordnance, great rules.
Protector: I have mixed feelings about what they did to this ship. I liked my more "ordnance" focus for the ship, the loss of the bomber and torpedo is really felt, since the fleet is based off of ordnance combat. You need to learn how to use it differently, those 90 degree turns effectively guarantee the enemy is always shooting against 6+ armor.
Emissary: this thing wins over the merchant in every way. it can take the grav prow, and has three effective versions for you to toy with. I take them frequently because for a 4 hit cruiser, they are armed to the goddamn teeth, and frequently are ignored. also.. they are cheap.
Warden: Better then the orca by far. faster and better weapon arcs.
Castellan: I can't agree with your assessment. For 150 points, you get more torpedo's then a Protector and the same as a hero. the 45 range guns are incredible if you keep them around a messenger or Custodian to benefit from the tracking systems. I don't take a fleet without six of these bad boys, and they always do the most damage.
Citidel: I don't know why they added this, aside from giving a Demiurge fleet a cheaper cruiser choice. I would take the bastion over this any day.
Dhow Rig and Convoy: finally, a cheap way to bring dhows to combat!! I love Dhows, and so should you.
Dhows: these are the most powerful escorts the tau have, and one of the best in the game. 3 batteries port AND starboard, 2 shields, and a 180 degree turn. sure they are slow for an escort, but they are a pain to kill, and can really dish out the pain to an enemy.
Kroot Warsphere.
Land one on a planet... watch the planet get eaten for the greater good.
Yes, look at it.. it's the fabrige' egg of doom and it can LAND. Omonomnomnomnom