Here's my take:
The only issue I see is user conflict. The speed and stealth from which an inexperienced e-biker can approach hikers, horse riders, and other bikers is substantial enough to create a bad situation. Banning e-bikers on this premise alone is not enough and rather an education process should be put in place to teach ALL USERS proper trail etiquette.
Now the sensitive subject: trail impact.
My opinion is that e-bikes will not impact trails any more that a regular user would. A e-biker can be categorized as an inexperienced user with limited physical ability. This is the primary market for e-bikes and thus will define the majority of sales. This user will not be attacking the trail on the way up, spinning rubber and letting the dirt fly, nor will they be attacking the trail on the way down, grabbing a handful of brake on every corner to come down from maximum speeds. This user is simply not comfortable nor physically able to ride in a manner that impacts trails more that regular users. There is more to biking that hammer the legs up and down trails: total body strength and physical ability/talent are required. This applies to technical climbing as well so some semi-secret, harder to access trails might still remain that way. There are exceptions to the generalization of who makes up the e-bike crowd: there will be fit, aggressive riders that will take advantage of the extended range and play time of e-bikes. My opinion is this will be a minority given cycling's core (read: knowledgeable) users understand the rewards of physical activity and the limitations of heavy, unwieldly bikes (1998-2005…)
Thus it stands to reason that trail impact being equal, we should welcome new users into the sport, whether they choose to get some help up to the top or not. The impact in revenue to all cycling associated businesses can only be positive given an influx of new members, thus a restructuring of sponsorship requirements from businesses would be reasonable. It could also be said that government funding could also increase with increased ridership. More money means more resources to maintain local trails.
Change is the only constant, and we would do well to acknowledge it and figure out quickly how it can work to our advantage rather than focusing on the negative aspects.