Aho is fine defensively. But Tkachuk is much better. Tkachuk also brings physicality and a pest like knack for drawing penalties. The very few more points Aho wil accumulate do not make up for this.
Going with either player is fine but "much better" does not belong in this comparison at this point in time.
I get that Tkachuk is an entertaining player but physicality and pest like qualities are way overrated when you have 2 players that both compete hard. When Tkachuk is out there hitting a guy or creating havoc in front of the net, Aho is also doing something positive without the puck, he's constantly anticipating plays and reacting to it, whether it's in the d-zone or o-zone. Just because Aho is not an agitator doesn't mean he's not tough to play against.
Being involved in the game the way Tkachuk is means he's bound to take penalties too, not just draw them. Aho took like 10 minors in the 82 games he played.
Im a fan of both players and the way both of them were able to play with such poise at this age was impressing to see. But there is no wide gap either way based on their rookie years. Coach won't have any problems sending these guys out there in any situation, but it'll be interesting comparison moving forward just because how different they are in personality.