The teleports that are -3 on block should be used to punish opponents who try to punish it on block wrong, same as any move that is -3 to - 4 on block.
Example, if you know you are -3 on block, and the opponent pokes you instead of going for a full block string, you can counter their poke with your poke, and be on advantage.
Same with Sonya's Cartwheel, same with Kung Laos Roll, Skarlets Red Dash into Low & Scorpions Take Down etc.
Bascially, anytime you think the opponent will block, don't poke, just full string instead, so if players do this to Raiden on his -2,-3 teleport block strings, he can counter them for punishing it wrong.