I see where you're going with this, and my program is kind of similar. I'll add a few things to think about.
day 1-horizontal push/pull
You might try press, rows, press, rows either as antagonist supersets (like Waterbury) or do all your sets of bench, all your cable rows, all your inclines, and then finish with DB rows.
day 2-quads,calves, abs
calf raises(in leg press station)
seated calf raises
I'd replace leg extensions with front squats. Also, search here for an article called "Diamonds in the Rough" about how to optimally train both the soleus and gastroc muscles.
day 3- off/cardio
walk/jog 3 miles at local park
day 4-vertical push/pull
seated shoulder press(db's)
See my comments for day one about alternating pushing and pulling exercises. Also, I would scrap the pulldowns and do chins and pullups instead.
donkey calf raises
There are a lot better hamstring exercises than leg curls (goodmornings, GHRs).
jog 3 miles at local park.
You didn't ask, but I do a program a lot like that:
lunges/stepups/unilateral leg work(sometimes)
I do the first couple of exercises each day for 5x5 or max effort or some other high weight, low rep protocol and do less weight/more reps for the later exercises. I think 4 days a week of 4-5 exercises for a 5x5 protocol may lead to overtraining. My program's a lot like yours, but mine lets you do vertical and horizontal pulling, vertical and horizontal pushing, and legs twice a week.
I kind of rambled here; if anything was unclear or you want any additional info let me know. Good luck.