- Firstly, setup sweepers can't set themselves up on Shuckle, as it caries encore and therefore can lock them into their setup move. Also, this is webs, so putting a scarfer there would be counter productive, then the speed drop of the webs makes it already far easier to revenge kill opposing mon, if they even find the opportunity to set themselves up against any mon of the team. For instance, Naganadel, Volcarona, Gyarados, Landorus or even Salamence if you want, can't as the only thing they can do is to set up on Shuckle, which can, as said before, lock them into their setup move thanks to encore.
- Then, you explained how the game might be much more complicated if the opponent removes the webs: as for setup sweepers, there are very few opportunities to remove these rocks without having a free setup turn for 4 mons out of 6 in the team. Even if it somehow has, Bisharp can still punish it thanks to Defiant.
- Finally, I agree that Lele does not pair well with priority, but I feel like what it brings, aka the ability to pressure defensive mons enough to ease the sweep of all the other mons in the team, does IMO overshadow its downside.