I noticed several things in the video:
1. Too many counters [I'll explain my theory on this]
2. Not too much teching.
3. Your opponent was either inexperienced with Marth and/or you know him'her too well.
Like the others say, there was too many counters I'd say. Maybe the right amount for that match against your friend, but for other more versatile players, it won't cut it. It seemed like from both sides, there was nothing but attacks and barely any grabs. If I were to play either one of you hypothetically and use counter everytime you approached me, I bet I would hit around the 90% range with counter. You guys need to open up your offensive game with throws and bluffs. You simply need to mix it up to keep your opponents guessing, same goes for your opponent.
Teching, just make a habit of teching "at the right time". If you continued to not tech against other advanced players, they wouldn't have to bother reading your evasive action, they can just **** you while you're still on the ground. But mind you, sometimes teching isn't the best option when struck on the ground, but for mindgames sake.
Also, you seem to be having trouble with shffls? One question, do you shffl with control stick or the c-stick and control stick together? Most of the time the c-stick shffling is easier and allows easier spacing. However there are players like Isai that can shffl and space just fine with just control stick.
On a scale from 1-10: 6/7 on account that you are definitely not the worst Roy on here, because I have seen much worse. Also, mindgames and technical skill could use work.
I'm sorry if I have offended in any way, and hope this helps somewhat.
btw, what you should note in that NEOvsKrazyJones vid is the spacing and timing NEO utilizes. Also his mindgames, especially the reading of the opponents "rhythm", which is not exactly clear cut. I also noticed some missed Fairs in your video, just work on timing, and i'm sure you'll get the hang of it.