You know what, I posted a really mean post before I decided to edit it.
Because, really, I'm a nice guy.
Is that 95lb a side on db preachers?
You have 4 curl variations in your program. And you are worried about stalling on one of them... I mean, really man...
What's your set/rep scheme?
Have you tired deloading and working back up?
I am not surprised that you are stalling on leg extensions etc. After squats + deadlifts your legs SHOULD be fried.
Here's a thought for you...
On the day that I work deadlifts, I also work chins or pull-ups. As my deadlift increased, my chins/pull-ups steadily decreased. This is because the increased workload of the deadlift had fried my back. If I decided to put chins infront of dl's, maybe my numbers would improve, and my deadlift would stall. If I re-tested my one set max for chins now I'm sure they have improved a whole shit load over a few months ago, despite the lowering in numbers of reps in my workouts.
The point is, I don't give a shit about how many chins I can do after doing DL's. My deadlift numbers are going up and that's the main exercise, the main focus, in that workout.
And sure, I've only been training for about 6 months. Maybe with your years of lifting experience you know so much more than I do.
Do you really really NEED to be seeing progress in, or even DOING, leg extensions, glute raises etc etc etc if you're seeing progress in squats and deadlifts? Do you really NEED 4 curl variations, and if you do decide that your inner upper bicep (or whatever) really needs the extra stimulus, then is it really important to be seeing progess on your lower outer (whatever) bicep exercise?
I assume that the exercises in the shoulders day are a standard press and a behind the neck press... do you really NEED both? Do you really NEED to see progress in both?
I hope this gives you something to think about.