As a Raiden mainer, these people piss me off. It gives the character a bad name, and just gives more fuel for whiny people I do beat legitimately to justify rage quits and temper tantrums. I don't consider myself an incredible Raiden, but I do try mix ups, BnBs, corner combos etc. I just like the character.
As both someone who plays Raiden a lot, and someone who's fought a lot of these bad ones, the key to winning against raiden spam is to think reactionary. If you manage to knock a Raiden spammer down, anticipate that they'll probably try to electric fly on wakeup, so try to goad it out more by dashing in but just blocking. In most cases they're panicky. In fact I'd say the golden rule is to always expect the Fly, even when they don't need to do it. I mean, its an addictive move even I can admit that I've had to keep myself from just doing it out of anxiety. Its probably your best bet to punish.
Some Raidens, like some guy named ValtielsAngel or something (who rage quits whenever you win), like to throw a lot of projectiles out in a corner to build up meter so they can do the enhanced version rinse repeat, and try to superman you if you move at all. Thats probably the most annoying type, but if you have a teleport or teleport attack of some sort you can probably time it just right so you get over there right when he fires one (though be sure to watch for the enhanced one being sent out.) If its a move that nets you a BnB then great, but if not then it'll just be a long, uphill endeavor.
I really hate to admit this because it annoys even me at times, lol, but anticipating a teleport and jumping backwards puts the teleporting Raiden in a really awkward position and it really throws off their concentration, so jumping overhead mixups are also a really good way to get into a raiden spammers head, or I'd say any Raiden really. That teleport is really, really good but if its just thrown out like candy it can be really harshly punished.
Although in my experience it rarely comes to this with spammier Raidens, when they are in front of you they usually try to kick your shins or sweep you. For all of Raiden's awesomeness, he kind of lacks a strong low hit game
It is basically turtling to an extent yeah, but unfortunately Raiden spam just sort of feeds off of frustration and impatience more so than most, so the best thing to do is to just be patient, and punish with fury. When it comes right down to it, people spamming just teleport, superman, and projectiles are pretty easy to flowchart and punish once you have it figured out you just have to be a little more reserved. If you've got good BnBs and your damage output when you can land it is good you'll usually outdamage their weenie tactics well enough.
If you play Cyrax, who's awesome enough as it is, you have a really sneaky anti-Raiden option at your disposal. If Cyrax does his teleport, for some reasion if Raiden does Electric Fly at the point you teleported, he'll go into his recovery animation after hitting the little "shockwave", as if he hit you...even though you've teleported safely to the other side. That gives you some time to retaliate, and even against Raidens that try to be good I have to say it's a very annoying little quirk he has at his disposal. lol (note: This is against Cyborg Cyrax, because of how he "splits" into little pieces during his port. I don't know if it works the same way against the human alt.)
I hope this is of some help.
