I argued very strongly last year that Ottawa 100% should have drafted last year, and let this year's pick go.
Math was in their favor for many reasons:
1. No matter how bad this season looked like it could be for Ottawa - finishing last is never a certainty. Many teams expecting to do horrible have great seasons (Col last year). Many times teams you don't expect have historically bad seasons and do worst than other expected bad teams (Col - 2 years ago). So even though things looked really bad for Ottawa for this past season - it was just as likely that they finish 2nd, 3rd or 4th from last in the league than last overall.
2. Even IF Ottawa finished last this season (and obviously - they did) - the odds the last place teams wins the lottery is 50/50 (that's for any of spots 1, 2 or 3). only ~20% chance at first place.
I think if they liked the player available to them last year highly enough (and they seemed to have been high on Tkachuk) - it was the right call to make.
The Duchene trade and the overpayment is still a horrible trade - but I have absolutely 0 issues with how they handled the draft picks once it was clear last year what their options were.