Howdy there! Approaching with Greninja can be a tricky task to do, believe me! I've been playing Greninja since day 1 on 3ds and even vanilla Greninja has a pretty hard time approaching. Greninja has a hard time approaching because most of his move can be unsafe due to his optimal moves for approaching like his aerials doesn't auto-cancel. His closest safe options for aerials is N-air and a properly space F-air, but like I said they have ending lag so you can easily shield grab N-air and F-air has a good amount of landing lag. Now reading may think I'm bashing his neutral game, but really I think he has a great means of the neutral, it's just you don't go ham with him like as an aggro play-style. Like characters like Little Mac and Captain Falcon, Greninja is more of a bait and switch character and a lot of people said this too that he is a
READ DEPENDENT character. Like if you want to have a safe N-air you have to read if they're shielding or anticipating an approach, personally I use N-air to punish whiffed laggy moves or cross-ups.
Here are some good tips and options I feel is great for approaching and being in the neutral in your favor or perfectly (and who ever is looking at this, feel free to read it! It's free from charge!):
- D-tilt: Down tilt is a really quick move and can combo into itself at low percents. It's a nice poking tool and lowers your hit box a bit. Also you can D-tilt into Jab 1 and Jab 2 (Possibly Jab 3, character dependent) and it's a true combo (Percent and character dependent)
- F-tilt: With the new 1.0.8 Patch (Or the Ryu, Roy, Lucas Patch) Greninja has a new move in his arsenal when it comes to approaches and the neutral. His F-tilt got a buff so it's MUCH fast and has a damage boost too. F-tilt also has good range and one of the most ranged moves Greninja has (other than his Water Shuriken). F-tilt can out range many things and good for footsies and can beat grabs since it's an attack. But most importantly, F-tilt creates a 50/50 at early percents when you hit your opponent and the 50/50 is dash grab (When your opponent shields) and N-air (To punish any other defensive options that is not shield)
- N-air: In speaking of N-air! N-air is a pretty nice move, but it can be unsafe on shield and like I said I really only use this for cross-ups or punishing
- Dash Attack: Now dash attacks are good zone breakers but it does not mean that it's safe all the time. Now this doesn't apply to Greninja it applies to A LOT MORE CHARACTERS. So really only use it on over committed moves that you can punish quickly with a dash attack
- Grab and Dash Grab/Boost Grab: Grabs is another great option but not your standing grab. Standing grab is really but, not a lot of range and can laggy. Dash grab/Boost grabs are much faster and have so much more range that standing grab.
Now my last thing I have to say is to master Perfect Pivoting, his D-tilt and his F-tilt is a lot better and can add pressure when you perfect pivot, now I know that there is most likely a thread about Perfect Pivoting. Perfect Pivoting can even make your U-tilt into an approach option!
Well that was a long message but I hope it help and if anyone needs any tips about greninja, I'm more than willing to help!