I think that 'the lion guard' is going to be a soft reboot..

[SimbasGuard]

Since Disney is trying to start a new franchise, doing a misleading trailer would not be a good idea. Because if you draw in a huge audience with the premier movie, then the premier movie does not live up to what people are expecting. No one will come back for the series.

I also think it would be unwise for The series not to maintain the standard that the premier sets.

So It looks like what we're getting with The Lion Guard is a series that does not seem to be aimed at Preschoolers.

What I'm hoping it turns out to be is something someone of any age can enjoy.

The only thing that worries me is the possibility of Lion King 2 being retconned out of existence. However if that is Disney intended to do that, having Kiara in The Lion Guard makes no sense. Now like several others have said, Disney could somehow make The Lion Guard and Lion King 2 work together and not completely retcon Lion King 2. That would be the ideal solution.