Currently, their are 14 recommended champions, 15 if you count Rammus. The last recommended champions to be released were Garen(August 2010) and Sona(September 2010). 9 others were released at launch, and the others were all releaesed in 2009.
Has it been too long for a recommmended champion to be released? They help new players get introduced to the game and tell them what champions are better for new players. I understand that we may not want to overwhelm new players with champions, but giving them new recommended options can allow them to find a role they like.
So, here are some existing champions I think should be recommended.
Xin Zhao: Targeted dash/cc, and other abilities revolve on simple auto attacks. His ultimate is his most difficult part, but in 1 on 1 duels it is a simple damage dealer combined with his passive.
Kayle: Again, no skillshots, a simple to understand passive, and targeted cc. Her ult is also her most difficult part, and can be a critical move in team fights.
Passive that gives you free stats, easy restoration, no skillshots, and a consistent escape and farming ability. The fact that he uses health is certainly a challenge, as some may kill themselves just spamming his skills.
Teemo: Auto attack things to death, no skillshots, and a passive and active movement speed increase. Mushrooms are not that difficult to use, though they do require more strategy then skill.