I agree with arctic_rogue that you don't need another D-man with your set-up. With weekly lineup changes I'd expect you'll be leaning on Karlsson and Subban pretty heavily and I'd be surprised if Myers or Smith see much action.
Koivu is a must-add in my opinion. The 2nd spot is more murky, but I'd look at Zajac and Callahan. It's just a gut feeling, but I've never liked Ennis much. Zajac is the top C in NJ and will play with Kovy, who he seems to have chemistry with. Callahan will probably be on the 2nd line in NY. I just don't think there are enough points to go around between him, Gaborik, Richards and Nash. He's solidly a PP2 guy. So my two guys would be Koivu and Zajac.
16 team, full keeper
19 roster players, 15 prospects
Stats: G, A, PPG, SHG, special teams assists, SOG, FOW, PIM, hits, blocked shots, +/-, W, SO, saves, s%, GAA, shootout saves
C: Crosby, Backstrom, H. Sedin, Boyle, Brassard
W: Voracek, Burrows, McDonald, Filppula, Dorsett, Hudler, Abdelkader, Bouchard, Ott, Zuccarello, Stalberg
D: Karlsson, Letang, Enstrom, Boyle, Giordano, Gorges, M. Stuart
G: Quick, Kiprusoff, Ellis
Prospects: Granlund, Pirri, Caron, Killorn, T. Johnson, Galiev, Corrado, Vatanen, Moore, Rundblad, Bachman, C. Johnson, Desjardins