I think the processing of the AV happens no matter what. The part about a creature getting a -3/-3 only happens after the processing of ancestral vision (or whatever) occurs. The word IF in the rules text dictates the timing in this case.
So by all means, please bolt my Wasteland Strangler that was already going to die to its own ability. The AV is still a goner.
If it doesn't work that way, it's entirely nonsensical. *Edit* wow, further digging indicates you can, in fact, cause the processing to fizzle by removing the target for the -3/-3. That's a poorly worded mechanic from an intuitive perspective, and I'm struggling to see why they couldn't have made it work a bit closer to how you'd expect it to work upon, you know, reading the card. Grammatically, prefacing a statement with "If" indicates a triggered ability, but not so according to the comprehensive rules, which only recognize "when, whenever, or at" as the words indicating a triggered ability. And sometimes "becomes"... Seems messy and/or confusing to link two events when the rules are already adept at handling them as individual actions. What am I missing? Why do this? The mental gymnastics required to retroactively loop the result of a choice you've made to the making of said choice is the goofy Catch 22 stuff that I thought modern magic rules were trying to avoid. Gimme back my damage using the stack at this point!!
So by all means, please bolt my Wasteland Strangler that was already going to die to its own ability. The AV is still a goner.
If it doesn't work that way, it's entirely nonsensical. *Edit* wow, further digging indicates you can, in fact, cause the processing to fizzle by removing the target for the -3/-3. That's a poorly worded mechanic from an intuitive perspective, and I'm struggling to see why they couldn't have made it work a bit closer to how you'd expect it to work upon, you know, reading the card. Grammatically, prefacing a statement with "If" indicates a triggered ability, but not so according to the comprehensive rules, which only recognize "when, whenever, or at" as the words indicating a triggered ability. And sometimes "becomes"... Seems messy and/or confusing to link two events when the rules are already adept at handling them as individual actions. What am I missing? Why do this? The mental gymnastics required to retroactively loop the result of a choice you've made to the making of said choice is the goofy Catch 22 stuff that I thought modern magic rules were trying to avoid. Gimme back my damage using the stack at this point!!