"which is based on a Liberal Party platform pledge to raise $3-billion in new revenue by eliminating tax breaks that primarily benefit wealthy Canadians"     

Key word is 'primarily', but some of the rumoured tax changes include higher capital gains tax and reduced dividend tax credits.  Sure the wealthy have more disposable income to invest, but this could also affect a portion of the middle class who have no pension and have worked hard to save and invest, or seniors who are drawing from their own investments.  

Higher investment taxes could also discourage investment and ultimately job creation in Canadian companies.  

If the Liberals are serious about waiting to see how much U.S. taxes are reduced, then they should absolutely take higher investment taxes off the table.