I don't think it's particularly practical to speculate about what Weezing could have been. :0 Let's stay on topic here and focus on what Weezing actually DOES have to work with.
So to me, it looks like we have a few distinct standard-ish sets emerging here... The semi-offensive Hazer, sans Stockpile, and the more defensive Stockpile variant.
Toxic Tank -OR- Physical Wall
Bold, 252 HP / 252 Def / 4 SpA
- Fire Blast / Flamethrower
- Thunderbolt
- Will-O-Wisp / Haze
- Pain Split
Weezing's token set from 4th gen... not a lot else to say about it, but switch it in on physical attackers and make them cry. Will-O-Wisp VS Haze is a matter of the user's preference: Wisp walls shit even harder than it already did, while Haze prevents setup sweepers from overpowering you with DD/SD/Bulk Up boosts, as well as making it a fantastic Inconsistent counter to boot.
Mixed / Dedicated Wall
Calm / Bold, 252 HP / 4 Def / 252 SpD
- Stockpile
- Pain Split
- Toxic / Will-O-Wisp
- Fire Blast / Clear Smog
This is the set to use for long term stalling and walling. The EVs and Weezing's natural physical bulk let it take physical and special hits alike, and after a Stockpile or three, it's going to be laughing at everything that gets thrown at it (a nice bonus to it as a wall is that it can't be stalled out by Toxic by virtue of its typing), especially with Pain Split for recovery. Toxic VS Will-O-Wisp is whether you favor stalling foes out, or taking physical hits even better than you already are. If choosing Toxic, then Fire Blast (or Flamethrower) is the recommended option in the fourth slot for hitting Steel-types (bar Heatran, who walls this set to hell and back). Clear Smog allows Weezing to laugh at setup sweepers, who otherwise might cause trouble for this Weezing's lack of an offensive arsenal.
These are two sets I'd like to see in the OP.
Thoughts?
Edit: Now with natures and EVs! :naughty: And modified (crappy) set titles! And some comments regarding usage (feel free to steal/paraphrase!)