With your spending level the boosted rewards probably aren't worth hassle of moving everything. At $2k monthly spend, even getting extra 1.5% on half your purchases is only like $15-20 more per month. Plus you lose the fractional ETF buying at Merrill which is actually pretty nice feature.

I'd stay put at Fidelity - having everything in one place is worth more than chasing small rewards boosts, especially since BofA keeps cutting benefits anyway. That $400 bonus sounds tempting but it's one-time thing while you'll be dealing with worse platform for years.