Watchtowerism has been without a viable doctrinal "energy source" ever since Fred Franz died in the early 1990's. They are truely running on fumes at this point, or as you put it so well, the battery is almost dead. Since Fred Franz successfully kicked out the best and brightest of his braintrust competition in the witch trails of the early 1980's his death really left the Watchtower Society in a pickle. Without an energetic and imaginative "Bible Scholar" who is adept at "mental gymnastics" no matter how misguided and looney, the Watchtower leadership has been in an intellectual vacuum for years now. This is a religion and, truthfully, all religion really has to offer are basically imaginative ideas held together by a sense of community and tradition. A comparitively young religion like Watchtowerism has very little tried and tested tradition to successfully recycle their time-failed ideas unlike traditional Christianity which has not relied on time-limited promises/ideas for 1800 years now.
In short, the only appeal of Watchtowerism over traditional Christianity is its DOOM & GLOOM "Bible-based" tm. AREN'T THINGS TERRIBLE ONLY WE KNOW WHEN Armeggedon time -lines " and paradise your lifetime" extra complicated "deep" understanding by God's only Earthly Channel. Without any updated or interesting DEEP (it was deep all right) understanding of Bible prophecy they now really have very little to offer someone seeking an alternative to traditional Christianity. The fire is out and the coals are smoldering. If someone comes along with some new twists and some charisma these coals can be reignited but how many Russels, Rutherfords, and Franzes are there? So far none in the Watchtower camp who've been left alone long enough to take over.... so they get fumes, coals and dying batteries.