Not sure if it's of any help to you Rob. I'm with Ancestry UK, when I clicked the link in the profile I was taken straight to the census page on the .com site. I must have already been logged in for something else recently. I logged out and tried again; this time I had to log in, at which point Ancestry lost the plot and asked me to search again, so yes it's a bit inconvenient. I had to go back to the profile to click on the link again, at which point I was taken direct to the census. I guess the reason I get taken straight to the census is because I'm in the UK with an account that lets me see all UK & Rep Ireland records. If the record were a US record I would have been taken to a paywall.
I like the external link templates as well, especially where there's an app to formulate them. But what you suggest may not be practical. If someone like me with a country, or region, specific account clicks a link and is taken to their own region, unless the record is part of the subscription they will hit a paywall anyway. For example if the link in your profile was to a US census record I would not be able to access it whether I went via the .com or .co.uk site, either one will present me with some form of paywall eventually. Your suggestion would be fine for those with worldwide access though.