MTG Salvation

Do mine eyes deceive me? Red protection and removal?

Pro's
Many problem creatures in Commander are big. That's what makes them a problem. However, once you range in to the 'problematic big' territory, these creatures usually have a larger power than toughness. This makes Laccolith Rig a potential kill on those creatures, or at least, gives you the ability to use someone else's attacker as a sniper, if you so choose.

You can also use it on your own creatures as an incentive to not blocking, as their most valuable creature will die regardless.

At the very worst, it's a super first-strike, to keep your blocker alive even through first/double striking defenders.

Also seems amusing if someone has a stuffy doll on the field, or when placed on a creature with wither/infect to deal with indestructibles.

Con's
It's an aura. It's removable, and if used on your own creature, can make it a 2for1.

They don't have to attack once its on theirs (red pacifism for 1!), or block if it's on yours.

Specific Generals
My Kazuul, tyrant of the cliffs deck runs a few permanents that force or encourage attacks. This could work well their.

Ruhan of the fomori could likely also use this, as a self enhancement to pick off other problem creatures, and to play a political card on the offensive.

Any others?

Couldn't you just put it on your opponent's creature and use it as pseudo-political removal?

That's actually what most of my post was about.

Most problematic creatures in EDH are able to (at the least) kill themselves; but you have no obligation to do that. You can use their creature as a consistent removal source (potentially). Or, at worst, have a R pacifism, as they refuse to attack with it.

Quote from ISBPathfinder

I just wish trample still worked with it

Trample may not, but flaring pain does.