It has been proven time and again that lowering a suspension to "fit" is the single best thing you can do to any motorcycle to increase rider confidence and enjoyment. Only a fool would advise against lowering if it is indicated. Touratech peddles a Hyperpro lowering kit for the F8 which claims 2". In actuality it is about one inch. It is the best thing I have ever done to the F8 for both the performance improvement as well as confidence/handling. I am 6', but have a 31" inseam.
I have many friends and GF's who have lowered their suspensions, and the feedback is uniformly positive.
If I rode only pavement or fire roads, I would have left mine alone. I suspect people who claim to be doing fine with an F8 and a 30" or less inseam are simply not riding it on agressive off road venues such as Lippincott Road and Steel Pass in Death Valley.
my favorite bike - R1200GS