While it is true that senators sometimes correct errors in bills passed by the House of Commons, this is not a strong enough reason to have a Senate. 

And if senators are all elected (which will take about 25 years to even happen, given that many senators are that far away from retiring), the Senate will not only sometimes correct errors, but also cause inefficient gridlock by sending bills back to the House with major changes (as the U.S. Senate does in the U.S. Congress).

Senator Colin Kenny and some other commentators claim that Senate committee studies are better than House committee studies but this is impossible to prove -- most people view studies as "better" if they agree with the study's conclusions.

As well, Senate (and House) committee studies and reports are just based upon the submissions of citizen groups and think-tanks and other organizations who issue their own public reports and lobby Cabinet decision-makers (who are usually not influenced much by committee reports).

Senate ethics rules are also so loophole-filled and weakly enforced that senators are essentially allowed to be embedded lobbyists for interest groups, usually corporations for which many senators are directors.

The simplest solution is to abolish the Senate, and to maintain the balance of regional interests that is currently in the Senate by adding MPs in the House of Commons from smaller provinces.

True, this would violate the democratic principle of representation by population, but the Senate already violates that principle even more.

As well, in any federation-type government such as Canada's national government, that principle is always violated to ensure protection and balance of regional interests in the federation.