'The Mackie will save him money and will literally eat the Polk.'
Today's PA speakers are not the junk PA speakers of yesteryear. All channel stereo on these Mackies (each speaker matching/voiced identical is both seamless and fantastic).
500 watt power handling vs. 125 watt
96dB sensitivity vs. 89dB sensitivity
10" woofer vs. 6.5" woofer
1.4" compression driver vs. 1" soft dome tweeter
Clean coasting reference audio playback vs. strained reference level audio playback (assuming 10' listening position)
Powering handling characteristics at 1 meter. (Besides more power handling headroom - Mackies are much easier to drive with a Receiver - they are a bit over twice as loud (7dB) with the same exact power)
see attached image.
One thing that may be true:
"Not many people can accommodate 5/7 big PA speakers."
Agreed - but just presenting a Pro Speaker option of the type that is often unconsidered.
One thing that is certainly not true towards the Mackie C200:
"One issue with going with all powered speakers is you need a receiver that has full pre-outs."
The Mackie C200 are passive speakers, meaning your AVR powers them just like any other speaker. They use Pro audio connections called Speakon or 1/4" jacks - but that's just an adapter at the end of regular speaker wire. Takes about 5 minutes tops to pop on each speaker wire. 3 phillips head screws - that's it. They use these types of connectors in mobile Pro audio, because when you are dealing with high power amplification you don't want to risk frying gear when regularly plugging in and unplugging your speaker wire for gigs using traditional bananna plugs or binding posts. The Speakon or 1/4" jack are still just + - connections, just designed so you can't accidentally short anything out.
Five of these speakon connectors are $13 bucks shipped:
The Mackies are just a suggestion, that's all. It'd be a heck of a system for the money. I don't know how you'd top performance for the dollar ---- if you don't mind the looks.