1. those could be very slippery when wet so if possible put down some sort of traction sticker or something on them to give grip.
2. getting out of the blind is going to be tougher than you think. With no hand rail there you will be fishing for that first step some. If possible, I would make the hand rail and extend it up to the blind itself so you have something to grab when your first foot is fishing for that step.
good call on the grip tape, I have some of that for boats that I am going to install.
Also, on just inside the door of the blind , I have two grab handles installed on the door frame
This is there you grab hold when going into and out of the blind.
When you are stepping down, you back out on your knees and you can hold onto the handle until your feet hit the first step.