There's not much in the way of substantial requirements that can be effectively included in a non-copyleft license, because to grant rights to end users in ways that will ensure that they can actually exercise them you have to put significant restrictions on the distributor. E.g. the LGPL managed to be "copyleft enough" to be incompatible with app stores, and still offers the end user very little that they wouldn't get from an MIT-like permissive license.