Wiercioch went straight to Denver after being drafted from the USHL, which means he would have had to play 4YRs to be a UFA. If he had spent another season in the USHL, he would have only had to play 3YRs before he could leave as a UFA. Given that he was a 2nd round pick and a good player, the risk of him staying for 4 full seasons and jumping ship was minimal.
Loheit, on the other hand, will only need to play 3 seasons for Minnesota-Duluth before he can become a free agent. And let's face it, he's a 7th round pick and will probably need at least 3YRs in college, which means if he develops successfully into a legit NHL prospect over the next 4YRs, in 2021/22 we'll be just another team trying to convince him to sign with us.
If we were New York, LA or Chicago, that would be one thing, as everyone wants to sign there, but unfortunately we're not nearly as attractive as a place to play. It's an unnecessary risk to take.