Was there ever a time when RRSP contributions made in the first 60 days could be used either for the year just finished OR for the upcoming year? I seem to recall that.

Yes, there was a time when you could use the contributions from the "First 60 Days of the Year" on the previous year or current year's tax return. Although I cannot find any documentation to when the CRA made this change, I believe it was around 2005/2006. And as a tax preparer, I totally agree with you that it is a hassle to file an adjustment.

I have found that doing these adjustments online through your CRA My Account is quite quick, often times the adjustment is processed at the same time the tax return is filed. And another thing is: if you use CRA's AutoFill service to import your tax slips, often times the RRSP which you never claimed will download to your tax return as an "Unused Deduction" and you are able to claim it on the current year.

Thanks for the answer! Don't know why CRA removed this flexibility. Setting up a CRA account for the first time is a hassle--you have to wait while they MAIL you a confirmation code! And worse, in the early days, CRA would cancel your account if it was left unused for a year (or it canceled itself after a year). That meant re-activating your account, waiting for the snail mail code. Don't know if they still do this. The problem multiplies when you're doing tax returns for relatives.