Rush 2112
I don't know if I entirely agree with you on me relying too much on z-drop mb for ledge guarding as I find it to be a good option at making your opponents life hell trying to recover, but I do see where you're coming from. If anything, I would say that I overcommitted on super laggy moves at the wrong time when I fully well know how risky they are. Mega Man is one of those characters that can cause a lot of mood swings depending on how successful you are or aren't.
I must say that playing the MM ditto feels really weird to me, especially against those like yourself who know what they're doing. At the very least though, I truly felt like I learned a lot from our ditto matches and can hopefully make better judgement decisions in the future.
It is a good option, but it seems like most of the time you are dropping it and hoping they run into it. Especially when you drop it so high. It already has a lower chance of killing than most ledgeguard options. From what I saw, as soon as they go flying offstage you get your MB in hand, making it obvious what you're about to do. If the opponent has a good recovery your chances of landing the zdrop are even less. If you watch our matches I was able to avoid it almost every time by UpB'ing to either side of it. The type of recovery your opponents has should determine your options. For example, LS against Captain Falcon works well.
If you watch my videos pay attention to my ledge guarding. It's very aggressive and varied. I get most of my kills from LS gimps, Dairs, and Bairs. I find the best use of the zdrop is to get LS up, position yourself at the ledge(with a roll if you have time), and short hop zdrop with timing. Instead of dropping it the first chance you get and hope for the best. Also, do it reactively not automatically. There was one time against Link where he was dead but your zdrop saved him. Watch his approach to time it correctly.
Yeah, I don't really like the MM ditto all that much and haven't done it in a while. That's why I switched towards the end. In the ditto pellets are often cancelled out so it's a different kind of strategy most of the time.
Watching your matches here are some thoughts. My opinion, of course. Some may disagree so just take from it what you will.
You pretty much never want to jump in and throw LS at close range. If you ever decide to throw it and you don't know for sure if it will hit, you always want to jump away. Use Cstick to throw it in the opposite direction.
When you grab and they are below, let's say, 80%, you should almost always Bthrow for the damage. Even if they are close to the ledge a Fthrow isn't going to get you much. At least with a Bthrow you rack up damage quickly. After a few throws it adds up, even when stale. Throw in LS and it's even better.
Do double jump Dairs instead of single jump. It's MM's best autocancelled move and can still hit most standing opponents, unless they are the short ones.
Dsmash is strong but you use it a bit too much. I would suggest forcing yourself to never use it, until you form a better habit. Then learn to use it on hard reads only, if you must use it at all. Try replacing it with Usmash or Utilt if you want to kill. Only recently have I decided to try and fit it in, and only when I can power sheild an aerial where the opponent keeps landing behind me. Yoshi's nair comes to mind. If they land in front utilt will always be my option.
Avoid approaching with Dtilt. Especially if they're are grounded with no other pressure being applied. Unless their shield is weak.
Learn to pivot pellet. It's one of the easiest things to do but I don't see very many people use it. I see you running away and turning around with MB or jumping pellet. Run away to about max pellet range, and turn around, and pellet. Even if it's not going to land it is effective for various reasons. Once you start doing it more often you won't have to think about it and it will greatly improve your spacing and pellet game in general.
Try to avoid or limit approach-landing with Fair unless it's a sure thing. Try a sweetspot nair or just Rush bounce to get into a better position.
Start doing ledge jump nairs to get back on stage. It's surprisingly effective and can often put you on the offensive.
Zdrop into falling LS is kinda cool when it works but not a good idea to use so often. It's too inconsistent. Dropping the blade from so high reduces the chance of it hitting and a good opponent will catch on quick.
Short hop pellets are great, but you should also do full hop pellets. It seems like the only time you pellet is approaching/retreating with a few short hops only. I don't recall any sweetspots or stopping aerial approaches with full hop pellets.
You do many things well but it does seem like your biggest problem is choosing high lag options instead of low lag. At some point I started to focus more on lagless moves and only doing a move if I will not suffer any/much lag after it. Plus being ready to shield asap. Like, in neutral I only use Fair while rising on a full hop. I don't use any smash attacks, except when I see a possible opening. I keep my distance and pellet/MB until I find an opening. Or LS and approach safely. I'll use RAR Bairs to cross up and Rush to escape. I would suggest you watch my matches to see this in action. I'll be uploading some new replays soon that are better than anything I've uploaded before. I'm pumped for a big local tournament on Friday : D I just might win it.
It also seems like you are doing stuff and hoping it will work instead of reacting and choosing the proper option. Try to keep your eyes on your opponent rather than yourself, if you don't already. That really helps.