Plante is progressing, but will be in tough to make the NHL, even with current players in the Oiler's defense corps. (corpse?)
His most important stats? 6'3", 225lbs, and 138 penalty minutes in 73 games (led the OKC Barons in Pims.)
That said, Edmonton has Foster (29) Whitney (27) Gilbert (27) Smid (25) Peckham (23) Chorney (23) Petry (23) on the current roster, traded for Kevin Montgomery, and signed Martin Marincin and Brandon Davidson. Edmonton will likely take RNH with the first pick, and then draft a defenseman at 19, and possibly another at 31. That, combined with picking up a similar player in Colten Teubert in the Dustin Penner deal, and I can't see an open slot at the NHL level for him.
In short, his window to make it is shrinking rapidly.
With his footspeed and decision making, even with his obvious edge to his game, he's in tough company. Of the young players, Peckham has separated himself from the group, and both Petry and Chorney have looked good in stints in the NHL. Plante's likely looking at another year in OKC, and if he struggles, might end up in Stockton as early as next season.