I agree with your view Ken. However aside from the risk of it not being right is the risk of your wife saying I told you so in 4-6 years time. There is nothing worse for families than issues over money.
My advice is that you both sit down with an independent financial adviser in the new year and whatever decision you make that you make it together. Even if you end up paying a fee, it will be worth it to know that you or your wife are comfortable with whatever decision you make.
Happy Christmas
Stephen