5 spades to KQ with 12 Milton Work points- ample to open under Acol (>11 points and >Rule 19), moreover
N deserves to know that S owns the 12 points. If S passes we could easily miss a decent contract
7 losers- fine to open
1S controls the first level of bidding for N/S- pre-empting value
S hand is a good basis for S or NT or even H contract
You get the spade lead if needs be
The rest of the field are going to open 1S anyway
Pass
Its a game of winning tricks: S only has one sure (slow) trick (when 1S contracting for 7 tricks- quite a shortfall)
The intermediates are very poor- not even KQ9xx in your showcase suit
Other honours are unsupported
Substandard points to open under a 13+ SAYC
Structurally a defensive and not an offensive hand, moreover
2nd position under (what could easily be) a heavy West
EW are not Vul so quite likely West will intervene
and in consequence N might well have to strain to bid now (in 4th)
NS are Vulnerable so more expensive to slip
Pencilling in average points and suits I imagine N hands will cluster to 11 points with shape 3,3,4,3, so the value bid is closer to 3S bid than 2S, something like:
xxx, Axx, KQxx, Qxx
I’ll pencil in a losing 1 1/2S, 1/2H, 1D and 1 1/2C, so it looks like a losing 3imps even on such an average hand

What am I missing?
Thank you
0deary