It is certainly correct that rebel pilots always try to do sneaky and cowardly attacks ... that fact has little to do with 'tactics' however. It is just because they are afraid of a proper dogfight against us significantly better trained tie pilots. As they are losing the war, they are turning increasingly desperate. Yes, I also had the pleasure of encountering a few of those supposedly clever rebels in a nebula. They couldn't even use their shields properly and the fight was over before it began. If you want to live a long life as a tie pilot, you need to learn a few tricks - and grow eyes on your back. To this date the best trick I ever managed to pull off in that field was a slight (of course I ensured that that little experiment was properly authorized) modification to my my own tie by turning it - so to speak - upside down. Or rather: backside-front. It was a bit difficult to transfer the engine section to a point just under the cockpit and the laser cannons just inside the 'engines' ... but it was worth it.
It surely shocked quite a few of those oh-so-sneaky rebels.
But I digress ...
Daniel, though you correctly mentioned that X-Wings were originally supposed to be employed in the Imperial fleet, you - obviously being a ground trooper - perhaps missed the rather sceptical - if not outright negative reception the prototypes were given in fleet circles. Nobody wanted to fly the ugly things. Don't know what our science department intended them to be - probably cargo tugs ... but certainly they would never have passed as proper fighters. I guess that's the reason why the rebels were able to steal them. Their security level dropped significantly only days before that event.