The Story: Add more choices to the story mode. It seems as if you are forced to do the same thing every time you play. Give a choice whether to come out of high school or go to college (college would get you a higher pick in the draft) and give an option whether or not you want cutscenes. Also, in free agency, you can go to any team without affecting their cap space, creating an amazing team.
Building Your Player: You can't make a Giannis-like player in the game. I think you should have the choice of what player you want to be like.
Example: NBA Live was actually ahead of 2k, as, in Live '14, you were able to make a player like Kevin Love or Pau Gasol at the PF position, and height/weight affected your beginning stats.
The Park: It seems that centers can dominate in any game of MyPark, simply because everyone else is either a SG or a PG. Give recommended courts for when you are playing based on positions and archetypes. Also, get rid of where you get kicked out for having too low of a score. People who face centers can get easily scored on and lose a lot of their progress. Speaking of progress, it seems as if you do one bad thing in Park, you lose a lot of the progress you have just made (I don't know whether that is because I usually play with guards or not.)
Improvements: Get better servers, show which archetypes can specifically guard which, allow specific types of players to be created, and give recommended park courts based on positions and archetypes.
Content: 2k is making better and better content every year, as I like the concept of new packs after every 2 weeks, but they use the same player too much and some not as often. Andre Iguodala started off the first two collections having cards, but other players could have been in the collection. I enjoy how they had collections that mainly focused on different positions (Lockdown focused on centers, Handles focused on guards etc.).
Collector Rewards are too difficult to get. I have spent easily $200 dollars on packs (because I am an idiot) and just now have gotten Antoine Walker and barely 1/3rd of the way to Kobe.
Packs are too expensive at the beginning of the year. You had to pay 200,000 VC for a 21 pack box for at best 1 Ruby at the start of the year. Lower the pack costs at the start and start raising them as soon as the cards get better.
Cards are still very statistically incorrect sometimes, as a John Stockton that's an amethyst only has 90 steal when he should have a 95 or 96. I also like how they had lower ratings at the start, but some cards that looked good on paper (Sapphire LeBron) that aren't actually that good.
Leagues: If you are in the Ruby League, you should play someone in the Ruby League. There are too many times where I have played in the Sapphire or Ruby League and I go against someone who is in the Diamond or Pink Diamond League.
The rewards of the Leagues are also very outdated once at the end of the year, as beating the Ruby League gets you a 20 Pack Box which is basically nothing at the end of the year. An MT reward like 10k or VC would also be acceptable.
Gameplay: First thing you'll know into a game is that they wander around for a good 10 seconds. I don't know if that's to keep a strong connection before the game starts or it was a bug. After that there are countless mistakes, as someone with 99 Ball Handling could get the ball stolen from them, you get blocked by a 6ft PG because they take a weak lay-up instead of a dunk, or even the passes don't go where you wanted and get thrown right to the defender. All of these are there just to keep the other person to stay in the game.
FIX RECEIVING A LOSS AFTER WINNING THE GAME
Some players have badges that are unnecessary to put on like Diamond Marc Gasol has Flashy Passer on him.
Improvements: Fix the servers, don't give momentum to the players online and give better rewards.