There are sites with many recommendations for mobile devices in their, e.g. wikia staff's, portability.wikia.com . While many things aren't applicable to wikimedia largely because they have some extensions that provide functionality not available here (e.g. Portableinfobox), and vice versa (templatestyles), many suggestions apply to all wiki sites
Generally though, wikia chose to use the nuclear option of stripping most mobile inline styling because they probably didn't want to bother with all the hacks wikimedia uses. Still, it is better to reuse whatever developers deem useful rather than starting from scratch here.