Well, if the team didn't have cap concerns then this trade doesn't happen. Perron is clearly a better player than Pääjärvi at this point in time, and a better system or not, a contending team doesn't make that kind of downgrade for a second round pick.
We are a better team next season with Perron instead of Pääjärvi.
However, we are a better team next season with Roy and Pääjärvi than with Perron, which is what it came down to for us.
We got good value given the circumstances, but we sold low because the marketplace was so limited by teams that couldn't afford to take salary on.
The other thing to look at is the future, as well. We can't afford to re-sign all of our guys as they exit RFA and get into UFA territory so sacrifices have to be made somewhere... and when we can get a young guy in his early years of team control like Pääjärvi in return for a guy getting expensive that isn't so bad.
Maybe next season the Blues are a little worse off without Perron but the payroll flexibility isn't just for this season, its for future years, and Pääjärvi has more room for improvement than Perron does at this point in their careers, with Pääjärvi at 22 and Perron at 25.
Heck some people have labelled Pääjärvi a bust when many guys his age are barely making the NHL before they have an impact.
I think this was a very good trade by Armstrong for a couple of reasons.
1) He turned an asset with declining surplus value into one with lots of surplus value. Perron is going starting to get expensive relative to his production and the Blues can't have that in players who are not franchise caliber. Pääjärvi will be cheaper than what he provides on the ice for the next couple of seasons since he's just starting RFA.
2) The asset he acquired better fits our lineup and system, so the possibility that we're actually improving the team with the swap in the short term is there.
3) Payroll flexibility. We'll have more room to sign Bouwmeester/Steen etc. next season, not just Roy this year.
Getting a younger guy like Pääjärvi is a huge plus. I don't think this trade was much of an overpay at all really and it works very well for us with the roster we have constructed.