Edit - I may have proven your point saying he needs to get acclimated lol
Sort of.
Its not so much that Elliott may not still turn into a decent NHL PMD, its that the Avs have needs other than Elliott will provide in the now.
Playing two units with risk taking PMD like Barrie and Elliott is not a great idea, even more so given that they are young and lack D men that are good enough to cover them to play with. Also worth noting that Holden is also a bit of a risk taker, putting those 3 in the lineup at the same time is not a great idea in their current development path.
I would argue the Avs need different bottom pairing D men rather than just more of them, as it is the only real way the Avs can improve the D core without risking the future or spending money poorly. They need to add a player or two to the bottom pair that has experience AND still has some game left in him/them that allows the club to use its other D men more effectively. As I have said a few time in various places, I would love to see the Avs sign Boyle and Morris and play them as the 3rd unit, moving Boyle and Hejda around as games situationally demand to play with Johnson.
Hejda-Johnson
Holden-Barrie
Boyle-Morris
with Guenin and Wilson as the depth D men is a solid way to improve the bottom end of the D core while not expending valuable assets in the now. It does not address the top unit needs totally, but it will increase the minutes the 3rd unit can play, taking stress off of EJ and whomever he plays with on the top pair. Hejda gets less minutes to stay fresher. It also gives the Avs two very solid depth D men at the NHL level. Siemens, Bigras, and Elliott can get their cups of coffee with the club as the season goes along without rushing their development curve. Nothing lost if Morris eventually loses a spot to one of them. The PP and PK both get an upgrade on the back end.