Jute's point about Fraser not being in the squad is a good one to mention here too. There may be personal reasons (I'm not convinced Clarke has ever been particularly enamoured with him) that he isn't in, but it does strike me as a bit strange that Armstrong is in the squad despite not making the Southampton side the other night (not fit, of course), with Fraser (a regular) not in.
It reminds me of Brown in the late nineties, when we just continued with the same players through loyalty and continuity, rather than regularly introducing new faces in order to transition from one campaign to the next. I'm fairly convinced that this will be the "last chance" to see at least half a dozen of these players in a Scotland squad, and I'm not sure what purpose it serves. Hanley, Cooper, Jack, Armstrong, McLean, Forrest are all guys that don't bring a huge amount to the squad and also won't be there beyond the summer (Fraser, at 30, probably has a qualifying in him). The Forrest one, especially, is just weird tokenism at its finest. Barron in for Jack, Max Johnston in for Hanley or Cooper, and maybe Stewart or Conway in for one of McLean, Armstrong or Forrest. Even Josh Doig in for another of the three just mentioned. Would our squad look any worse? Not really. Of course, I'm only mentioning these lads as I've watched the u21s a few times and I'm aware of them, I'm sure there are some other unearthed Scottish grannies out there with grandsons in their early twenties. These guys might not even be the future of the national side, but at least they have a future and we can begin the process of transfer to them.