Just putting it out there.
But as an example to encourage discussion I will suggest something specific off the top of my head.
Change the "Rez Cost" of Ice to a "Rez/De-Rez" cost. Any time the Corp would be able to Rez a piece of ice, they could pay the same amount to De-Rez it. This would allow the Corp a money sink in event of Siphon, as well as an option to "turtle" a piece of Ice from a surprise Parasite/Datasucker until such time as the corp could execute a virus purge and save the Ice, or just never re-rez the ice and keep the parasite around in a less recurrable state, eating MU in exchange for keeping the Ice de-rezzed.
Alternatively, make "De-Rezzing" a piece of Ice a free action on encounter, again as a counter to Parasite Datasucker. The runner still gets an advantage in that they effectively bypass the Ice, but the Corp prevents the Parasite from going to Heap where it would become recurred.