We're flogging over old ground here. The main error was an ATC one, no doubting that. However waving the situational awareness flag as you were, IF the Shorts pilot had heard the MD80 lined up on the same runway, PERHAPS it could have been averted (been thrashed to death already)
If we wish to recount "personal experiences", I had the opportunity to plug in and watch Montreal Terminal earlier in the year. Talk about confusing. Let's picture a somewhat new BA pilot entering that airspace for the first time. Must be daunting. As I have said several time, in a BUSY terminal environment, what's the effin need or point aside from the "because we can".