So as the title says I feels a bit odd to me. It feels quite unstable, really pointy in the front when you just ride normal, like any tiny movement in the bars will give you a massive overreaction. When turning at faster speeds I feel like it doesn't want to rotate like I would want it to either. This can be quite a problem when jumping as the bike can almost get away from you when running in for a big jump. I can't really cruise-ride the trails, it feels like I have to really man-handle the bike to do what I want it to do. Is this normal? I've previously only ridden HT bikes, NS Majesty was my latest bikes many years ago now, but I remember that thing being dead solid under me when doing tricks or going down small trails in the forest. My riding-mate has a Canyon Strive CF7.0 and his bike is much much more stable in the front, and when he tries mine he agrees that he thinks it feels quite unstable. Maybe the slashes are that way? Any feedback would be great just to hear if its just me or if this is a general consensus around the bike. Edit: I changed to a shorter stem (from approx 55mm to 40mm) and a smaller handlebar (from 820 to 800). I think it made a small difference but nothing massive.
A FS bike rides quite differently from a HT bike. Your body position may not be adequate for the new bike. These new FS bikes require a more neutral position than rearwards (at least when I had my HT, I rode it much more rearwards) and vary between different brands. Your slash also has a much slacker head angle, and maybe you are not used to it and don't see the advantages (more confidence-inspiring on chunkier or steeper terrain) but more 'vague' steering ( requires more manhandling on tight trails).
You could also have too light rebound or inadequate compression on your fork, making your front end unstable. Or your fork may be malfunctioning. Your front tire may also be a cause of your problem (too much inflation or not enough grip).
I really doubt your Slash is a bad bike. I have a friend with one (a prior version) and he likes it very much. I tried it once and it seemed very capable.
Can't pinpoint what the real problem is, but the aforementioned causes could be a starting point.