Urgh, no, please, no.
THis game is rated for players of the age 12+, why do we need mechanics for infants?
There is 'convenience' and there is 'making the game so easy that a baby could play it'.
It takes 3 to 4 casts/shots to learn of your AoE range / maximum range on Archer (needed for skills).
Remembering it is not a hard thing to do. I think an indicator for this is a horrible idea.