Agree 100% with JoshC1977 comments. The game is remarkably well balanced out of the box this year for a person who is just getting going with Madden again. I think you should play some games on Pro or All Pro stock to get a good feel. I'm not sure if you have to play a few seasons before adjusting sliders but you definitely should log 5-6 games and then make a note of what feels off to you and your game style.
If you are decent with the stick you will not want to stay on Pro for long as you really need All Pro to get a good fight from the CPU. But Pro would let you get your feet wet as you get familiar with the game again.
After you have some experience it will be easier to tweak sliders to adjust a little or at least when you come looking for a slider set you can state what you are looking for and get better answers more targeted to your desires.
For example I have tried several All Madden slider sets that are highly recommended and I just can't complete with the CPU at all....now I use the Browns exclusively so that could be a factor. When I think the QB accuracy is way off it might be because of my QB. Someone playing as Green Bay may find the same slider set perfect cause...well...you know....Aaron Rodgers.
Good Luck.