Gon,
I don't use Metia or Ladol because Shelby has never, ever failed and costs me 0 SP. I agree the -2SP removals are more fair than other removals (and thus, they are never used) however, it's not just SP arithmatic; you have to consider two things:
1. Field advantage. This is the main draw of using a removal. The reason I think Volfied is the most fair removal is because it just factors in this aspect and not the second aspect. The field advantage alone can sometimes make or break the match and that's why I don't think the second aspect should create any net SP change.
2. SP drain. Something I think the designers failed to appreciate in the early removal SS designs which led to slight nerfs to some removal SS.
As for the so called "risks," in 30 matches so far, my non-shelby removal SS failed to return something just once and I still won the match regardless. I don't feel like I'm taking even the slightest risk and I believe the benefits far outweigh any potential setback. No player has been able to counter it in all those matches and I'd wager that no player will counter it for at least 100 matches.

