I think one would never want to advocate it as a measure to help the poorest seniors, because it will leave them out. However, it is true that currently we do allow people to split their CPP, for instance, with a spouse, and we allow that to be reflected in a lower tax burden for the person who shares his or her pension. We also allow spousal RRSPs, so if you're willing to save money in an RRSP that is in your spouse's name and belongs to your spouse, you can save some tax. We do allow it already for certain types of retirement income if there is a real transfer of those assets of the pension over to the spouse.
An argument could be made for extending that to employer-based pensions, the kind of pension income that is covered now by the pension splitting rules, but it would require, as you say, that there be a real sharing, a real shift of title over those pension assets over to the spouse.