@Soulfox -- that is where a good attorney or accountant can be very helpful. Estate attorneys and accountants make it their business to keep up to date on laws concerning inheritance taxes and subtle changes to strategies involving complexities such as step-up basis evaluation.
There's nothing in the world wrong with getting one of those experts to review your plan and give an opinion as to whether it is still effective and suggest a "tune up" to get it in line with current inheritance tax laws.
When it comes to step-up basis in particularly, keep in mind that valuation pops up all over the place. For example, in some states the value of homes is frozen at a certain point for senior citizens for the purpose of property taxes. When that house is sold -- or passes through inheritance -- to someone who is not a senior citizen, the value might be "stepped up" to reflect the present market value of the house and it will be taxed at that rate. In one of those states, then, it is very good to know how the tax laws in that regard work before you buy a house.