As I'm sure you know, I'm part of the "Traditional!" cheerleading group, though not because it's straight up "better" than the Roth, more just to make sure people consider it mathematically and don't simply end up Roth-ing by default. But in your case (though I don't have super-detailed access to your numbers/future), while I still might lean towards more into the traditional 401(k), you're close enough to the mid-point on the balance between the two types, with unknowable future factors being the main thing that would clearly push you from one to the other. So I'd say that your 50/50% approach seems like a good choice for now, that way when you reach a point where you know what the future ended up being, you can be happy about the 50% where you were "right" and ignore the 50% where you were "wrong".
I think that tax rates will generally go up in the future, but perhaps not at all for the "poor", so the closer you expect to be to "poor" in your retirement, the more advantageous the traditional 401(k) becomes (because the marginal rate for the poor might not rise, and deductions/exemptions shield a huge part of your income from tax), and that's before I even considered the potential of a consumption tax eating into your Roth money that you mentioned.
Going off on a tangent regarding Tim's comment about having 5 years of income accessible, I wonder how often that's an issue that needs to be explicitly planned for. I'm 14 years into a ~20 year working career, and have been maxing out my tax-sheltered savings for the last 8-10 years, and then about 5 years ago started contributing to a brokerage account, not to keep it "available", but simply because I had nowhere left to shelter it. I already have ~10 years of living expenses in that brokerage account. I guess it's more of an issue for people with lower incomes and expenses, for whom the tax-sheltered limits are large enough to absorb almost all of their yearly savings. But for me it's not even close to enough (this year I think I'll end up saving >$50k, with only $22k of it shelterable)