It's not an uncommon thing for me to introduce new people to games I enjoy however recently I have noticed that when initially selecting Warframes all I can really do to help them choose between Loki, Excalibur or Mag is to direct them to this wiki and get them to do a little research which, don't get me wrong, is not a bad thing but it's jsut a little excessive.
I am aware that DE have mentioned about continuing to improve the tutorial to explain more subjects more effectively so my suggestion is to integrate the Warframe Profile videos into the game as a 'preview' button underneath each warframe option. I don't mean click the button and it redirects you needlessly to youtube to watch but i mean taking the raw video file and actually putting it in the game so it plays like a triggered cutscene (Don't bitch at me about complications, i KNOW this is one line of code). the Warframe Profile videos are very informative and gives new players all the information they need to select their gaming style and to compare each warframe while saving a ton of time! :3