Your information is outdated
It was indeed possible in the past, but was fixed with the release of U21 (though whoever put together the notes clearly knew very little about the class since Air-lore is mistakenly called 'Lore of Air'). (https://www.lotro.com/forums/showthr...-Release-Notes).
I like the suggestion ainor made, however as long as there are strong cross-trait possibilities, traits that aren't clearly worth picking up over cross-trait possibilities will be left out. If it is implemented, make the heal strong enough to turn it into a better option than cross-traits picking up extra blue goodies!