I only saw the first match so far. Your playstyle may have changed since September, but here's what I saw:
One thing in general was noticeable- powershielding. I think it's an "I play ROB and I grew up with sidestep>downsmash" thing, and this applies to at least 75% of ROBs (including me sometimes), but you need to improve the speed and accuracy of powershields. 0:37 and 1:28 are good examples of this. I know it's a natural response to hit the shield button when you hear thunder jolt begin, but when you press it too early, all it does is drain your shield and give you lag after the attack hits you. Thunder Jolt is slower than it seems, and is definitely slower than it sounds. 1:34, on the other hand, illustrates this point- you were able to fire a laser and still powershield in time. Some of your other powershields were good, but little things like this go a long way in keeping yourself out of bad situations in the long run.
1:42- You learned your lesson- don't try to beat that with nair... or anything else. Either recover high and airdodge through thunder (which IS possible) or hover for a bit, cancel up-B and reflect thunder with side B if you see it coming. If you're coming from below the stage, go for the ledge and use invincibility frames to punish thunder or get back on the stage. This doesn't mean to fly to the ledge ASAP (you CAN outlast a pikachu that jumps off to get you) because you don't want to be floating into a ledgedropped aerial or ledgedropped thunder. Taking an extra half-second to float up/cancel upb with fair is usually worth it because it gives you the option to react instead of play rock-paper-scissors offstage
1:55- lol. I like it =P Might not be reliable but it certainly worked so I can't complain.
2:01- I like the nair stall, giving you a clear path to the ledge instead of trying to land with a falling Nair. You don't want to get shieldgrabbed or hit with another thunder
2:02- you decided that you DID want to get shieldgrabbed or hit with another thunder by trying to land with a falling Nair instead of grabbing the ledge or recovering high. Instead of up-B-ing immediately again, drop below the edge and up-B into it, automatically grabbing it
2:07- Close, but not quite. In cases like this, you can hit with a Nair and sometimes a Fair and make it
back offstage safely but you went for too much. Take the extra moment to float offstage to get a better position. Even if you don't hit pika during thunder lag, there's enough ending lag to let you have a better chance of making it back than trying to nair and keep going.
2:11- Much better, even if it was the only option at the time.
2:38- to be fair, falling Nair is/was also a bad habit of mine. It's such a sucky feeling to get shieldgrabbed after it though, so getting punished repeatedly eventually helped me break the habit.
3:05- Good
Last stock- I feel like you were fishing for the KO too much, throwing out a LOT of upsmashes where uptilts might have been better, or forward smashes where forward tilts might have reached. You ended up KOing with dsmash, which could have been DI'ed better, but you took a lot of damage in the process.
4:50- You were dangerously close there. Going for the Dair was not worth putting yourself in that position, especially with some fuel already gone, with pikachu at 0%, and with you at 110%
Just working on avoiding thunder both onstage and offstage and dealing with thunder jolt will save you a lot of % as well as saving a lot of your shield. Watching the end again, I noticed that when hanging on the ledge, you nearly always got back onstage by pressing the control stick. Just something to think about, since the pikachu only punished this once (though it was a costly once, giving you about 20% at the end that you really didn't want).
Edit: ftilt is a good punisher, and outranging pikachu is nice
Edit #2: ROBcide video up!
http://www.youtube.com/watch?v=fx81Pc-VjLo
Works against other characters but remember to face away from the stage, otherwise you die and the opponent survives.