If the league finds that its too debilitating not being able to bid on Minor league players,
You could modify the rules that instead of it reading no minor league eligible players can be bid on,
You could re-work it to no players with 0 NHL games can be bid on.
OR
A player needs to have play X (5/10/20) amount of games before being available to bid.
That would kinda appease your want for the bidding wars and being able to still sign some minor league eligible players that are surprise NHL guys but still maintain the high value of the draft picks.