Agree with everything here but the teleporting Warriors into rapid fire distance. The problem with this is that rapid-fire distance is also "in range to be assaulted by the enemy" distance, which four out of five times results in the Warrior unit's destruction.
Warriors need to hang back as much as possible. Park them on objectives, preferably in cover and contribute long range Gauss Flayer shots to the fight - but don't be afraid to Go to Ground for the improved cover save. Individual Warrior units can rarely achieve anything worthwhile on their own, so keep them safe. It might help to have some sort of "buffer" unit that can intercept enemy units that are looking to kick your Warriors off of objectives. Scarabs can do this decently, as can Tomb Spyders or even Wraiths.
In the ideal situation, you'd have your Warriors standing on an objective in cover, nice and spread out so as to avoid complete annihilation at the hands of any accurate blast weapons. You'd also have some Scarabs nearby, safely out of sight ready to lend a hand as needed. Now let's assume that the enemy is rushing your Warriors with a Rhino full of Tactical Marines, or Battle Sisters, or even a Chimera full of Guardsmen. Your number one priority in this situation is to do everything in your power to disable that Rhino before it carries the enemy unit any closer to you. The Warriors can take a few potshots at the transport as it comes, hopefully immobilizing it. Failing that, Destroyers and Heavy Destroyers can finish the job. Once the transport isn't going anywhere you can pretty much leave the vehicle alone.
In the enemy turn, he'll probably disembark from his transport and close the distance on foot instead. In response, you want to move your Scarab swarms into place to intercept, rapid fire the living hell out of the enemy unit and then do one of two things - either assault the oncoming foe with the Scarab swarms if you're confident that the enemy won't beat destroy all the Scarabs in the first combat round, or you can just leave them where they are, preferably in a line formation so that they don't give the enemy unit any choice but to go through them to get at your Warriors. If all goes well, the enemy will shoot and then charge the Scarabs, destroying them and then becoming stranded right in front of your Warriors. A second round of rapid firing should pretty much deal with most units. If not, allocate Destroyer and Immortal fire as needed to mop up any stragglers.