It's all tax dependent, and may require a favorable taxable/tax-deferred allocation. And maybe a little luck at predicting tax rates, investment gains, and personal needs.
Figure out your taxes at age 70, when you have to take RMD's. In fact the RMD for age 73 is 1/24.7 = 4.05%, and they only get higher after that. Kind screws the taxes, though you don't have to spend it all. Given that I've liquidated all of my taxable accounts by then, the only "voluntary" portion of my income will be how much to withdraw from the tax-deferred accounts, at least some of which (maybe all due to SS) will be at my marginal tax rate.
I'm 63 now, with no income other than taxable investment distributions and capital gains. I can do pretty much what you're suggesting. Except if I keep going like that, SS and a pension and RMD's will give me a marginal tax rate of 24% or more (28% if tax rates revert, higher if anyone cares about the deficit). So at the very least I need to Roth convert whatever I can now at less than a tax cost of 24% (or whatever).
In fact there is also a benefit to Roth converting even if the tax rate of the conversion and the later withdrawal is the same. It's equivalent to being able to contribute some of your taxable account to your Roth IRA. So, if you are paying taxes on a significant taxable account, like me, it's worth it to go ahead and hit the top of the 24%/28% bracket using Roth conversions. Especially with a long time between conversion and withdrawal.
Also if you currently file jointly and one spouse dies before the other, imagine what your taxes will look like as a single. Probably too late to Roth convert then.
And yes, you might not want to Roth convert everything and die with only a Roth account. Though that might be easier to manage. Leave enough in the traditional IRA accounts to fill in the lower tax bracket(s). Then make Roth withdrawals to avoid going into a higher tax bracket. The whole idea is to get that traditional IRA money out at the lowest tax rate.
I think this will be my last year of really big Roth conversions. The next 10 years will have small conversions up to the 10% bracket with capital gains overfilling the 0% CG "bracket". After that SS and RMD's hit and we'll just fill up the 22% tax bracket with traditional IRA withdrawals and use Roth withdrawals as needed.
There is also a possibility that we could go for healthcare subsidies for the next 2+ years, but I have most of a year to figure that out.
Lots of complications there, but my general rule of thumb is to withdraw from the traditional IRA when I can at lower tax rates (or equal) than RMD's will see, and if I don't need the withdrawn funds for expenses it becomes a Roth conversion. That should get you at least 80% of the benefits without all the calculations.