Appears you are currently saving 25% (plus whatever state tax rate) on your traditional deductions.
If you switch to all Roth now, your marginal withdrawal rate - even at (~$110K/yr + tax) expenses - will be only 15% (plus whatever state rate). Given that*, you should not switch to all Roth now.
At the very least, contribute enough to traditional to get below the 25% bracket. If you continue to contribute the full $18K (or more - do you have a TSP/403b/other option in addition to the 457?), you could also do "tax gain harvesting" by taking capital gains from your taxable account and paying 0% federal (plus whatever state) if you stay within the 15% bracket for total taxable income.
Check again in 10 years or so to see what your expected marginal withdrawal rate is, and adjust if needed. :)
*You can play with the
case study spreadsheet,
www.i-orp.com, or other software to estimate this for yourself.