The first game I played with these sliders I got hammered on the ground - I think it was against the Eagles. Since that game I've started to motion my D-line and LBs pre-snap to match up better.
So if the offense line up with 2 TEs on the strong side you better motion your D-line to avoid the blockers to get to the second level. If one of those big guys reaches your 2nd or even 3rd level it's over!!
Also, lets say you have a cover 2 play called. Pre-snap you think it's going to be a run you can also "show blitz". What this does is move one safety into the box to crowd the LOS.
Beware though!! I just had a game against the Ravens. Coming into the game I thought that if I was going to win I needed to keep Ray Rice in check, so that was my first priority!! It was like the CPU knew... First play of the game they line up in the strong I, go play-action and Flacco hits Torrey Smith for a 75 yard TD. Oh well, they are not going to do that again, right? Well, when it was all said and done Flacco had thrown for 6 TDs and I lost 52-20
BUT I kept Ray Rice to 50 yards on 22 carries.
My point being these sliders, just like Wiz said, forces you to choose. What will your focus be on defense!? You can't shut everything down all game. It's a chess match - just like what you see on sundays!!