Processing Rules: Allow the modification of a evar set using merchandising syntax

[#1]

See Incident: 

Clearing a merchandising evar via process rule [Incident: 140404-000121]

I tried writing a processing rule as such: 

If evar4 equals any (Shopping_Cart | PAGE_) then delete the value of evar4.

Pretty simple, yes?  As it turns out, since evar4 is a merchandising evar and it's value is set on the product string, processing rules cannot see it or change it. 

I would like to be able to access and modify evars and events in product strings from within a processing rule. 

[#2]

Processing rules are so woefully underpowered honestly I don't know why Adobe even bothered and it's doubly head-scratching that they make you get certified for it, despite it being literally the lowest threat level for changing things out of all venues to change things. 

I wish they would open up VISTA rules to us instead

[#3]

p.s. if you can swing it, get your Adobe Analytics implementation into DTM; it will basically render Processing Rules moot.