I know I'm pretty new to this... but a 5 hour + block seems to be pretty unusual yeah? We've had a lot of bad luck the last while with groups of 2+ hour blocks

Sy.
No
And for the CPU miners, let me repeat:
If you are seriously trying to make something off of CPU mining, you should not be with slush. You should find yourself a straight up PPS pool and stay there. Please take the advice to heart.
There is nothing wrong with Slush's pool that's causing your returns. It's working the way he has designed it. CPU mining doesn't pay off, so Slush won't support it.
Don't get me wrong, I'm not trying to blast you, just saying how it is. It will benefit you to find a straight up pps pool.