First I'll say I'm going to end up getting this game.
I liked the first game,I liked killing zombies with all of the weird weapons,I didn't like the first ones really hard main story aspect though,
I ended up just playing the first game saving survivors and playing side missions,with that being said,should I expect the same with this or is it easier to beat the main story line?
 
I know that the psychopaths in this are still hard to beat,or at least some of them are,but is the main story line really hard or just challenging?

In my opinion, the second game is virtually identical in every respect. All the same fun is still there, and all the same frustration is still there. The same things that pissed you off will be back in full force, so be ready to expect that when you go into it.
 
I never found it to be challenging myself, but it can be difficult at the same time. I like to differentiate between the two because challenging means there is something you can usually control, whereas difficult might imply that the designers setup the game so everything works against you.
 
You still save survivors under strict time limits. You still complete story missions within strict time limits. You still run slow, you still typically have more missions/survivors to rescue at any given time than are possible to achieve. The psychopaths are still frustratingly designed and feel like a chore to slay. The control is still clunky and rigid feeling and well.. literally basically nothing has changed in those respects. You can combine weapons and you are in a new (but still mall) area, but overall it just felt like an expansion pack to me - nothing that warranted a completely new game.
 
But that's just my opinion - I'm sure others may disagree with me.

The game is so much easier than the first. It's so easily possible to do a perfect run through with all survivors, all sidequests and S rank ending. Especially at lvl 50. It's not challenging, unless you are attempting it for the first couple of times or at low levels. Psychopaths are not fairly balanced but at high levels with knife gloves they go down so easily.