Every bike i've ever owned has had panniers fitted from an F650 Funduro with really wide BM cases to a K1100LT with the same type of box mounted close into the bodywork and a huge topbox the same as the plastic 1150GS one but with the addition of a backrest/speaker mount. My 1150GSA had the original BM alloy boxes and top box which I changed for 35/41 litre Zegas which were never really off the bike as they were too handy for carrying stuff and not too obtrusive.
I've never really noticed any bad handling problems except in severe cross or headwinds but then I usually ride pretty slowly....!
With the HP2 it's either the Zegatex 'soft' luggage system and a tankbag or the 29/35 litre Zega boxes which I like and miss not having anymore.......!
I guess you either love or hate panniers, I like them a lot( though I've not had any catch fire.......yet!!)