Having used "Full" Revit for a number of years I'm finding Revit Lt very frustrating purely because of some features are missing and they're not major features. I understand that Lt is supposedly aimed at users editing projects created in Full Revit so can understand why certain things are missing but given that Lt users are likely to still be working collaboratively with other disciplines or Full Revit users there are some items that, to my mind, are essential and should be included in Lt... none of them major features btw.
1 - Visibility/Graphic Overrides of linked Revit models in View templates: You can do it for model, annotation and imported categories so why not linked Revit files?
2 - Transfer Project Standards: Inclusion of some items that are currently omitted from TPS in Lt, for example Railings.
3 - Linking/Exporting with Co-ordinates: Whilst it is still possible (though far more convoluted) to set a project with the correct co-ordinates in Lt it's not possible to share link in another Revit file with the same co-ordinates and have them be recognised or export a CAD files (dwg, dgn etc.) with the set co-ordinates for anyone else involved in the project, be that another team member or consultant, to utilise.
None of these are really that major but definitely class as essential for anyone working in a BIM Level 1 or 2 project especially where there's a CDE utilised.