Regarding Cruisers: My favorite tactic is using a Fusion Torch to cut into one of the Engine Compartments, then storming the craft from there, rather than the the Elevator Shaft of Death. This approach allows me many melee opportunities in most cases.
Still risky; remember that the enemy often knows exactly where you are. More than a couple of times I've made an advance into a UFO from an 'unexpected' entry onto to have a door open and grenade tossed in my face.
Melee assaults don't necessarily need to be a mad dash straight for every target in sight - there's a nice balance between turtling in smoke and balls-to-the wall sprints that I've found useful in both the open-field portion of UFO assaults and attacking hideouts. A mix of melee skirmishers, some heavier fire support, and scouts allow for rather quick clearing of the Battlescape up to the doors of the craft without being overly conservative.
I find that melee charges are more events of opportunity (where you can run out, shield bash, then run back into cover or stun all visible targets), OR make sense after you've substantially weakened the enemy followed by smoke grenades.
As for fighting against Psi attacks, I thought I read on this forum that a gal can't be targetted unless she's been seen by some enemy. Thus it's possible to control who will be the Psi-rod just by managing LOS. By which I mean abusing smoke and getting a few parrots killed. Or pick scouts that have been psi-screened, or don't carry any weapons. Not always easy to do in practice, but certainly possible.
The way it's apparently supposed to work is that the enemy doesn't know your location until you're spotted, after which they know it for X turns, where X is equal to the 'Intelligence' rating of the spotting character.
In practice I've had units Psi assaulted even when I'm 100% sure they weren't spotted, so who fucking knows. That said, even if they need to make initial LoS, you often get a situation where one guy gets controlled, then spots everyone, and then another guy is controlled before the Intelligence timer runs out who then spots, and thus the merry daisy chain continues.
