This team is so deep at forward that adding Luchanko has some major diminishing returns compared to adding Allen. Our 4th line when going down the list for points among forwards is Nurmi-Read-Van Bommell, which could easily be a weak second line or an elite 3rd line on most teams in the league.
Before Haltunnen was returned and Blake Montgomery arrived, a case could have been made. We have forwards that fit every role at this point and when you think about the probability of winning the OHL/Memorial Cup with the current roster versus adding Luchanko, it's not going to be a major change. Luchanko wouldn't be on the first powerplay unit (already have 5 elite players that he won't bump off). We already have 4 strong PK forwards (Cowan, Barkey, O'Reilly, Sim), so he isn't a big help there. Faceoffs, he's a 52% which is good, but it's not like he's at 60%, so again, not a stepwise addition.
I think with Allen, this team top-to-bottom is a much stronger than last year's roster which went to the Memorial Cup final. Retaining Hawrey would make competing in the coming 3 years a possibility. I get the allure of adding Luchanko, and I wouldn't be that upset is Mark does so (nor do I begrudge the people that believe it's the right move), but I think this team is near perfect already.