I have a Maximus X Code but was in a similar situation. I started with an air cooler on my 8700k but wasn't happy with the temps or the noise. I switched to AIO and all is well.
It comes down more to your chassis/case than your motherboard. Most AIO coolers require very little clearance. I have the Corsair Hydro H115i and the CPU block is only slightly larger than the socket itself and doesn't interfere with RAM clearance at all. I could have every RAM slot occupied with no problems.
As for the tubing, it's going to be depend more on your case and the model AIO you get. Some have tubing from the side which could interfere with RAM but most Corsair ones have the tubes coming out of the front now which is ideal.
Radiators can be mounted with the tubing on the left or right. I have a huge case but even with the case, I couldn't get the tubing to work on the right hand side since it hit my hard drive cages. With the tubing on the left, it fits fine.
You just need to find a case with enough room to fit your radiator and you should be fine. Most case specs these days will tell you what size radiator they can fit and where at in the case.
As for the pump concern, this is also my first AIO and I was nervous. Yes, the pump can and will fail one day but most have 3-5 year warranties and by the point, I'm probably upgrading something anyway. If the pump fails, your system will simply power itself off. With air coolers, you also run the risk of a fan dying and the same thing happening.
I think the better temps, less clutter and less physical stress on the motherboard is worth the downside of a potential pump failure one day. Keep in mind, your car also has a pump and radiator. Do you worry about that failing every day?
