What are your thoughts....

3 players. You are player 1 with 4 balls left, 2 are easy and in open and 2 are safe touching on the cushion.. When you pot one do you try to leave completely safe and hope player 2 misses but somehow leaves it safe (otherwise you are left with 2 safe balls and hit 'n' hope) or leave the 2nd easy ball for player 2 so player 3 is left with the last 2 safe balls and is forced to open them up.

I think it's a smart choice when there's 3 or more players, to sometimes assist the player behind you in a safety.
And in the situation you described, not only would you do that, but also protect yourself when your turn comes back around.
Like chess, you have to look 3 moves ahead

Yep, a lot of looking ahead in cases like this, even sometimes if there's, say, 5 balls left on the table in a 4-player game and it's your shot. There's a chance you could be left with just one ball to aim at. In the situation you described, I'd either set player 2 up like you said (thereby forcing player 3 to hit and hope and maybe open up one of the safe balls) or I'd actually try to develop one of the safe balls so that I'd have something realistic to aim for when it's my shot again.

If 3 players are left set the next player up if you feel you will be in trouble next shot so you leave the next player an easy safety.

What i try to do is if i have a pot on with angle to cannon i would try cannon and hope the cannon brings the object ball off the cushion into open play as nothing worse than a ball on the cushion.

Based upon the comments from opponents i got for leaving an easy pot in a recent couple of games i am surprised no-one has said it is bad sportsmanship to leave it on. Just wanted validation on what i did.

Mind you the comments i got in this situation were nothing like the abuse i have received when i intentionally foul in 8 ball! that really upsets people.

If it gives you the better chance to win then do what is necessary in my opinion. May that be in killer or any other type. Aaron i am the same mate but i don't get much abuse for it, i have always played to win otherwise what is the point in playing, you don't exactly play to lose do you...

who cares play to win simples