In the 2015 NFL Draft there were (as far as I can tell) 0 returned missionaries drafted. That is 0 out of the 23 Senior RMs playing D1 football around the country in 2014. 7 of the 23 were invited to mini-camps or signed as UDFAs.

It is not my intention to say one way or the other whether or not BYU is doing enough to change this fact, just to present what I was able to find on this subject.

BYU: 10 Senior RMs on 2014 Team, 0 Drafted, 4 UDFA Opportunities
Not BYU: 13 Senior RMs on 2014 Rosters (list below), 0 Drafted, 3 UDFA Opportunities

Tucker Hancock (WR, AFA)
Harrison Wilfley (DL, Cal)
Hamani Stevens (OL, Oregon)
Siale Hautau (DL, Oregon State)
Iona Pritchard (TE, Oregon State)
Junior Salt (OL, Utah)
Westlee Tonga (TE, Utah) - UDFA - KC Chiefs
Chris Van Orden (P, Utah)
Jefferson Court (TE, Utah State)
Craig Harrison (QB, Utah State)
BJ Larsen (DL, Utah State) - UDFA - Buffalo Bills
Joe Summers (OL, Utah State)
Kevin Whimpey (OL, Utah State) - UDFA - Pitt Steelers

https://docs.google.com/spreadsheets/d/1-L6z2jROtyc9zTqdegwLUSFE7FshWZGhpnoEui1qc2A/edit?usp=sharing