Jorgen
World's Strongest Fairy
Paralysis and Screens are two things everyone pays lip-service to when talking about offensive mons in GSC. How many times have you heard "Charizard is great with Screen support" or "Marowak absolutely wrecks with paralysis support"? But, nobody really uses screens or dedicated paralysis moves all that often. It's not to say that they aren't useful moves, but still, for how necessary they seem to be for a lot of mons, you'd expect more use out of the strategy. Instead, the most common form of paralysis spread is bundled as a "bonus" into STAB damaging moves (i.e., Thunder, Body Slam), and Screens just aren't used very often at all outside of the odd MonoKou, and even then, Reflect is typically used more to fortify defenses against Snorlax rather than set up an offensive push.
This is indicative of one thing, really: focusing on Screens and dedicated paralysis moves to set something up is probably not an optimal strategy. These setup moves get poor distribution (most things only really have Toxic as a pure status move); most mons that get these moves generally have other things they want to be doing (Sleep Powder on Egg, Sleep Talk on Zapdos, Psychic to help Starmie beat things it should be beating); and most Pokemon that like these moves for support have critical failings preventing them from being consistently useful (e.g., Marowak, Machamp). Screens also run out of time in just 5 turns, whereas paralysis gets shaken off by Rest, so these moves are short-lived and either shoehorn you into a tight window for action, or require you to keep spending turns not only setting them, but switching in the Pokemon that use them.
Basically, screens and paralysis are difficult to abuse in any sort of meaningful way. Trying to set these up for some sort of sweep or wallbreaking spree will typically leave you with inconsistent results. This isn't to say that Screens and Twave should be avoided in their own right, but you should kind of just use them for their own sake and try to find moments to be opportunistic, rather than trying hard to incorporate them into your team or trying to make them an integral part of your core strategy.
This is indicative of one thing, really: focusing on Screens and dedicated paralysis moves to set something up is probably not an optimal strategy. These setup moves get poor distribution (most things only really have Toxic as a pure status move); most mons that get these moves generally have other things they want to be doing (Sleep Powder on Egg, Sleep Talk on Zapdos, Psychic to help Starmie beat things it should be beating); and most Pokemon that like these moves for support have critical failings preventing them from being consistently useful (e.g., Marowak, Machamp). Screens also run out of time in just 5 turns, whereas paralysis gets shaken off by Rest, so these moves are short-lived and either shoehorn you into a tight window for action, or require you to keep spending turns not only setting them, but switching in the Pokemon that use them.
Basically, screens and paralysis are difficult to abuse in any sort of meaningful way. Trying to set these up for some sort of sweep or wallbreaking spree will typically leave you with inconsistent results. This isn't to say that Screens and Twave should be avoided in their own right, but you should kind of just use them for their own sake and try to find moments to be opportunistic, rather than trying hard to incorporate them into your team or trying to make them an integral part of your core strategy.