Sherlock Holmes is an unparalleled genius. Warlock Holmes is an idiot.
A font of arcane power, certainly. But he's brilliantly dim. Frankly, he couldn't deduce his way out of a paper bag. The only thing he has really got going for him are the might of a thousand demons and his stalwart companion.
Thankfully, Dr. Watson is always there to aid him through the treacherous shoals of Victorian propriety and save him from a gruesome death every now and again.