Dumba was the top pair (5v5) RD last year, even when he was dragging around Goli's dead weight for ~20 games.
Dumba's 5v5 on ice was at 1453:51 ToI (179 mins higher the Spurgeon), 18:24 ToI/g (2.09 mins more than Spurgeon), 1.86 gf/60, and 2.02 ga/60.
Brodin/Dumba had 821:11 ToI together, 2.27 gf/60, 1.61 ga/60, 58.49 gf%. 2.46xgf, 2.46xga 50% xgf% (for a direct comparison of a potential Brodin/Faber pair)
Dumba without Brodin was 632:40 ToI, 1.23 gf/60, 2.56 ga/60, 2.3 xgf, 2.59 xga, 46.96% xgf%
No. I don't think Faber will be better than Dumba's team leading 5v5 ToI, or that a Brodin/Faber pairing will be better than a Brodin/Dumba pairing. I think Faber can match Dumba for special team play (no PP time and 2nd PK unit). I do think Faber's number will look better than Dumba's due to him getting a much more sheltered role.
I'm also not counting on a Brodin/Faber pairing happening out of camp. This is a coaching staff that preaches balance up and down the lineup. I think they'll try Brodin/Spurgeon (again) and Middleton/Addison. Then it will be Middleton/Spurgeon (again) and Brodin/Addison. Faber will be sheltered with Merrill (or Goli) on the 3rd pairing until Addison falls out of favor (again).