USGrant1962
Thinks s/he gets paid by the post
I think there's high likelihood one of you will predecease the other.
Which is why I don't understand one spouse leaving their tIRA to the survivor when the survivor has plenty to live on without the added tIRA funds & the increased RMD's drive them into higher tax brackets as you describe.
Instead, go ahead and leave your IRA's, or at least part of them, to the ultimate beneficiaries directly (assuming their tax bracket will be lower). The added benefit of that is the beneficiaries won't have to empty the larger lumped together tIRA in the same 10 year period, offering the opportunity to keep tax rates down over a lengthier period.
Then maybe I don't know what I'm talking about.
I'll second Midpack's comment - this is a real gem of an idea that had not occurred to me.
I always defaulted to the spouse as the beneficiary, not thinking about the actual needs or the tax hit from single filing. I really need to think about DW and I each leaving 1/2 of our tIRA/401(k) to each other and 1/4 to each son. In case of an unfortunate passing, like you said "the survivor has plenty to live on...", our boys could buy a house or pay down a mortgage, and Uncle Sam probably takes a little less. What's not to like?
These gems are why this forum is go great