Rotel RA-1592 MK II or something else to deliver around 200W to B&W towers around $3000?

 @yukispier

I currently have the B&Ws but nothing else.

Budget is still hovering around 3K... but it could be expanded in the next few weeks

So you need at minimum these components:
1) Preamp
2) Amp
3) Streamer
4) DAC
5) Cabling
6) Audio rack?
the 3K is not much to work with.

....I’m more sold on building a better system with separates for the same price.

I think you have this backwards.  While separates perform better than integrates, integrates have significant cost savings by reduction in casework and cabling though at the expense of a little performance - it's a tradeoff.  For the best price/performance, integrates are the better value especially if you are on a limited budget.

... putting most of the budget into a very good power amp and getting a pre & dac that will be OK for now but upgrading those components in the next year or so.

In high-end audio, the each component in the entire audio chain matters.  If you attached a quality amp to mediocre upstream components you'll get mediocre sound.

A better solution would be to build a system you can enjoy now but with the flexibility for future changes/upgrades.  

I like the Elac Alchemy:
*2.5k DDP-2 Preamplifier/DAC/Streaming End-Point and maybe the
*1.5k DPA-2 Stereo/Mono Amplifier
designed by Peter Madnick of Constellation Audio fame.  Plenty of positive Audio Alchemy reviews and this next generation should be better.  You can save more by buying used, and you can upgrade individual components later.  

There are a couple of early 90's solid state McIntosh power amps l

The technology for high-end audio is constantly progressing so generally speaking performance today is better than what has come before.  This includes the sonics of amplifiers.  Trying to save $ by buying vintage usually comes with a significant reduction in sound quality vs newer designs for the same $.  When buying vintage electronics, make sure you know what you are getting vs other alternatives.

“A better solution would be to build a system you can enjoy now but with the flexibility for future changes/upgrades.”

I thought that is the direction I am headed getting a proper amp with a midish level pre/dac combo.  I have everything else covered besides some decent speaker cables.  I think that the system will still be enjoyable to listen to without a $4000 preamp while I’m saving up for the upgrade.

My set-up: Simple 5.1 system.  B&W 805 D3's for the fronts, 700 series HTM71 S2 for a center, and a pair of 705 S2's for the rears.  Marantz SR6015 receiver.  I use a Rotel RMB-1585, a 5 x 200W multichannel amp to bi-amp the 805s and power the HTM71 center channel, with the Marantz powering the rear 705 S2's.  To answer your question, the Rotel amp is magic.  Rotel would power your speakers beautifully.  I don't recommend any Rotel processor however as I have had a lot of problems with an RAP-1580 in the past.  

+1 @kennyc 

I also think an integrated is the best bang for the buck in this price range. Either take one with a dac and buy a better dac later or buy a dac now.