Halley's Comet comes around every 75 years. From what I can gather on Wikipedia the comet is not spinning that fast, has a large elliptical orbit, and has been recorded since 240 BC returning on a very regular schedule.
Why would we NOT use Halley's comet as a probe? We already landed Philae on Churyumov–Gerasimenko going 135,000 km/h. Is it that much of a stretch to land it on Halley going 254,016 km/h? (The Sidereal rotation period is ~4.5 times longer for Halley.)
Isn't this rock a super-good candidate for a long-term solar system exploring probe?