Typically, if you come around a corner and see casters, you can just duck back out of line of sight and wait for them to come to you. If you're out in the open, you can use Movement infusion or Rampage to quickly run back out of line of sight, or use a targeted teleport if you have one.
Alright, and one final question, just to make sure I haven't colosally missunderstood the point of this class: During Rampages, I'm supposed to just use the regular melee attack, correct? And outside Rampages, I'm supposed to use talents?
(Disclaimer: I only won with Cursed once, on normal/adventure difficulty.)
You can bump attack if you are safe. You don't have many activated abilities, so against tougher enemies being safe is usually a result of using your activated abilities to lock them down and then you have nothing left to do but bump attack until your cooldowns wear off or you have to run away.
Rampage is about mobility and/or damage output.
You only activate
Rampage if you need to run quickly to avoid death. I frankly can't think of a better use for it than emergency movement.
When Rampage procs on its own, its more of a damage boost that lets you take free steps between attacks. Note that Rampage proc usually means you are taking big hits, so you get +2 duration from repositioning and absorbing damage without even thinking about it, to offset the lockdown talents or shield/heal/debuff removal inscriptions you use to stay alive long enough to escape to a position of advantage. I completely ignored Rampage duration when deciding what to do next in my winning run.
In my opinion the point of Cursed is being a cunning predator using your unlocked talent trees Strife and Endless Hunt (and Slaughter to some extent). You see everyone in the area through walls and around corners. You decide who you are going to ambush to get the best advantage. You jump out and start unloading debuffs and damage, hopefully tearing them to shreds before they can recover. You move and choose targets tactically to make sure enemies can't get the upper hand, but if you can't keep off the debuffs or damage, you run away snarling to lick your wounds. And then you come back, pick off anything that strayed from the pack, rinse and repeat.
To me, Gloom and Rampage are support trees. They are zero maintenance ways of making your life easier as you go about your normal business. They rock, and you could spend about 30 class points and a category point on them without buyer's remorse, but they aren't what you do for a living.