This is an incredibly fallacious statement, since the Avatar is a crucially important character within Awakening (with measurable significance among Chrom and Lucina, in-game story-line wise) and is a defining aspect of the game (as well as encapsulating the player's personal experiences with Fire Emblem as a whole - the grand-master tactician behind every critically-essential decision on the battlefield). The Avatar shouldn't be overlooked, especially if Sakurai is truly invested within interesting character ideas.
Also, I truly believe Lyndis would be a great choice for character selection, so I am certainly not against her inclusion (in the very case my response would be mistaken as being antagonistic towards her).